<SEC-DOCUMENT>0001209191-21-037563.txt : 20210603
<SEC-HEADER>0001209191-21-037563.hdr.sgml : 20210603
<ACCEPTANCE-DATETIME>20210603135024
ACCESSION NUMBER:		0001209191-21-037563
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20210528
FILED AS OF DATE:		20210603
DATE AS OF CHANGE:		20210603

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Voinovich Michael C
		CENTRAL INDEX KEY:			0001806753

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36613
		FILM NUMBER:		21992042

	MAIL ADDRESS:	
		STREET 1:		15985 EAST HIGH STREET
		CITY:			MIDDLEFIELD
		STATE:			OH
		ZIP:			44062

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MIDDLEFIELD BANC CORP
		CENTRAL INDEX KEY:			0000836147
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				341585111
		STATE OF INCORPORATION:			OH

	BUSINESS ADDRESS:	
		STREET 1:		15985 E HIGH ST
		STREET 2:		P O BOX 35
		CITY:			MIDDLEFILED
		STATE:			OH
		ZIP:			44062-9263
		BUSINESS PHONE:		4406321666

	MAIL ADDRESS:	
		STREET 1:		15985 EAST HIGH STREET
		STREET 2:		P O BOX 35
		CITY:			MIDDLEFIELD
		STATE:			OH
		ZIP:			44062-9263
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-05-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000836147</issuerCik>
        <issuerName>MIDDLEFIELD BANC CORP</issuerName>
        <issuerTradingSymbol>MBCN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001806753</rptOwnerCik>
            <rptOwnerName>Voinovich Michael C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>15985 EAST HIGH STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MIDDLEFIELD</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>44062</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-05-28</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1748</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23.9848</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3748</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>held in Rabbi Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-06-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1057</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23.9944</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4805</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>held in Rabbi Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1040.549</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>held in IRA (McD)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2250</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>held in Roth IRA</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4062.296</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>held in IRA</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Includes shares acquired under the MBCN Dividend Reinvestment Plan.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Michael C. Voinovich
by James R. Heslop, II
Power of Attorney</signatureName>
        <signatureDate>2021-06-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24.4_989920
<SEQUENCE>2
<FILENAME>poa.txt
<DESCRIPTION>POA DOCUMENT
<TEXT>
LIMITED POWER OF ATTORNEY FOR
SECTION 16 REPORTING OBLIGATIONS


	Know all by these presents, that the undersigned's hereby makes, constitutes
and appoints James R. Heslop, II, Michael C. Ranttila, or Donald L. Stacy,
signing singly, as the undersigned's true and lawful attorney-in-fact, with full
power and authority as hereinafter described on behalf of and in the name, place
and stead of the undersigned to:

(1)	prepare, execute, acknowledge, deliver and file Forms 3, 4, and 5 (including
any amendments thereto) with respect to the securities of Middlefield Banc
Corp., an Ohio corporation (the "Company"), with the United States Securities
and Exchange Commission, any national securities exchanges and the Company, as
considered necessary or advisable under Section 16(a) of the Securities Exchange
Act of 1934 and the rules and regulations promulgated thereunder, as amended
from time to time (the "Exchange Act");

(2)	seek or obtain, as the undersigned's representative and on the undersigned's
behalf, information on transactions in the Company's securities from any third
party, including brokers, employee benefit plan administrators and trustees, and
the undersigned hereby authorizes any such person to release any such
information to the undersigned and approves and ratifies any such release of
information; and

(3)	perform any and all other acts which in the discretion of such
attorney-in-fact are necessary or desirable for and on behalf of the undersigned
in connection with the foregoing.

The undersigned acknowledges that:

(1)	this Power of Attorney authorizes, but does not require, such
attorney-in-fact to act in their discretion on information provided to such
attorney-in-fact without independent verification of such information;

(2)	any documents prepared and/or executed by such attorney-in-fact on behalf of
the undersigned pursuant to this Power of Attorney will be in such form and will
contain such information and disclosure as such attorney-in-fact, in his or her
discretion, deems necessary or desirable;

(3)	neither the Company nor such attorney-in-fact assumes (i) any liability for
the undersigned's responsibility to comply with the requirement of the Exchange
Act, (ii) any liability of the undersigned for any failure to comply with such
requirements, or (iii) any obligation or liability of the undersigned for profit
disgorgement under Section 16(b) of the Exchange Act; and

(4)	this Power of Attorney does not relieve the undersigned from responsibility
for compliance with the undersigned's obligations under the Exchange Act,
including without limitation the reporting requirements under Section 16 of the
Exchange Act.

	The undersigned hereby gives and grants the foregoing attorney-in-fact full
power and authority to do and perform all and every act and thing whatsoever
requisite, necessary or appropriate to be done in and about the foregoing
matters as fully to all intents and purposes as the undersigned might or could
do if present, hereby ratifying all that such attorney-in-fact of, for and on
behalf of the undersigned, shall lawfully do or cause to be done by virtue of
this Limited Power of Attorney.

	This Power of Attorney shall remain in full force and effect until revoked by
the undersigned in a signed writing delivered to such attorney-in-fact.

	IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of this 5th day of February, 2020.





                                         /s/ Michael C. Voinovich
                                         Signature


                                          Michael C. Voinovich
                                         _________________________________
                                         Print Name



STATE OF

COUNTY OF



	On this ___________ day of ____________, ______________, ________________
personally appeared before me, and acknowledged that s/he executed the foregoing
instrument for the purposes therein contained.

	IN WITNESS WHEREOF, I have hereunto set my hand and official seal.



                                         _________________________________
                                         Notary Public



                                         _________________________________
                                         My Commission Expires:

</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
