<SEC-DOCUMENT>0001209191-23-043842.txt : 20230731
<SEC-HEADER>0001209191-23-043842.hdr.sgml : 20230731
<ACCEPTANCE-DATETIME>20230731165021
ACCESSION NUMBER:		0001209191-23-043842
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20230703
FILED AS OF DATE:		20230731
DATE AS OF CHANGE:		20230731

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TURK CAROLYN J
		CENTRAL INDEX KEY:			0001286841

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36613
		FILM NUMBER:		231128001

	MAIL ADDRESS:	
		STREET 1:		15985 EAST HIGH ST
		STREET 2:		P O BOX 35
		CITY:			MIDDLEFIELD
		STATE:			OH
		ZIP:			440620035

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
		FISCAL YEAR END:			1231

	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/A
<SEQUENCE>1
<FILENAME>doc4a.xml
<DESCRIPTION>FORM 4/A SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2023-07-03</periodOfReport>

    <dateOfOriginalSubmission>2023-07-03</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001286841</rptOwnerCik>
            <rptOwnerName>TURK CAROLYN J</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>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-07-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>291</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>26.80</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>31313</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares acquired under Director Compensation program for members of the Board of Directors of The Middlefield Banking Company.</footnote>
        <footnote id="F2">Shares are held TOD spouse.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Carolyn J. Turk by Julie E. Shaw Power of Attorney</signatureName>
        <signatureDate>2023-07-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<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 hereby constitutes and appoints
Michael C. Ranttila, Rebecca J. Braheney, or Julie E. Shaw signing singly, the
undersigned's true and lawful attorney-in-fact to:

(1)	execute for and on behalf of the undersigned, in the undersigned's capacity
as an officer and/or director of Middlefield Banc Corp., Forms 3, 4, and 5 in
accordance with Section 16(a) of the Securities Exchange Act of 1934 and the
rules thereunder:

(2)	do and perform any and all acts for and on behalf of the undersigned which
may be necessary or desirable to complete and execute any such Form 3, 4, or 5
and timely file such form with the United States Securities and Exchange
Commission and any stock exchange or similar authority; and

(3)	take any other action of any type whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required by, the undersigned, it being
understood that the documents executed by such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted.  The undersigned acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned, are not assuming,
nor is Middlefield Banc Corp. assuming, any of the undersigned's
responsibilities to comply with Section 16 of the Securities Exchange Act of
1934.

This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned's holdings of and transactions in securities issued by Middlefield
Banc Corp., unless earlier revoked by the undersigned in a signed writing
delivered to the foregoing attorneys-in-fact.
IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed
as of this 8th day of May, 2023.






                                                Carolyn J. Turk

_________________________________
						Signature


                                                Carolyn J. Turk

_________________________________
						Print Name



STATE OF Ohio

COUNTY OF Geauga



	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>
