<DOCUMENT>
<TYPE>EX-21
<SEQUENCE>4
<FILENAME>b39786aiex21.txt
<DESCRIPTION>SUBSIDIARIES OF THE REGISTRANT
<TEXT>

<PAGE>   1
ALPHA INDUSTRIES, INC. AND SUBSIDIARIES


                                   EXHIBIT 21

                         SUBSIDIARIES OF THE REGISTRANT


<TABLE>
<CAPTION>
Name                                                                  Jurisdiction of Incorporation
----                                                                  -----------------------------

<S>                                                                   <C>
Alpha Industries Limited                                                         England

Alpha Industries GmbH                                                            Germany

Alpha Securities Corporation                                                     Massachusetts

CFP Holding Company, Inc.                                                        Washington

Trans-Tech, Inc.                                                                 Maryland

Alpha FSC, Inc.                                                                  Barbados
</TABLE>


</TEXT>
</DOCUMENT>
