EXHIBIT 21 SUBSIDIARIES OF RICHARDSON ELECTRONICS, LTD. Name of Immediate Jurisdiction of Owner(s) and its/their Subsidiary Incorporation Percentage of Ownership Richardson Delaware Richardson International, Inc. Electronics, Ltd. 100% Richardson Virgin Islands Richardson Electronics Foreign International, Inc. Sales Corporation 100% Cetron Delaware Richardson International International, Inc. Sales Corporation 100% Richardson Canada Richardson Electronics Canada, International, Inc. Ltd. 100% Richardson United Kingdom Richardson Electronics (Europe) International, Inc. Ltd. 100% Richardson France REL Holdings, Inc. 99.3% Electronique SNC Richardson Electronics UK Ltd. .07% Richardson France France Richardson Electronique SNC S.A. 99% and Richardson International, Inc. 1% REL Holdings, Inc. Illinois Richardson International, Inc. 100% Richardson United Kingdom Richardson Electronics Electronics (Europe) Ltd. 100% UK Ltd. Richardson Italy Richardson International, Electronics Inc. 90% and Italy SRL Richardson Electronics, Ltd. 10% Richardson Spain Richardson International, Electronics Inc. 88% and Richardson Iberica, S.A. Electronics, Ltd., 12% Richardson Germany Richardson International Electronics GmbH Inc., 98% and Richardson Electronics, Ltd., 2% Richardson Japan Richardson International, Electronics Japan Inc. 100% K.K. Richardson Singapore Richardson International, Electronics Pte Ltd. Inc. 100% Richardson Mexico Richardson Electronics, Electronics S.A. Ltd. 100% de C.V. Richardson Netherlands Richardson International, Electronics Inc. 100% Benelux BV Richardson Brazil Richardson Electronics, Electronics Ltd. 100% do Brasil Ltda. Richardson Australia Richardson Electronics, Electronics Ltd. 50% PTY LTD Richardson International, Inc. 50%