EXHIBIT 21 SUBSIDIARIES OF THE GENLYTE GROUP INCORPORATED DECEMBER 31, 1999 The Genlyte Group Incorporated has the following subsidiaries, 100% owned, except as noted: Genlyte Thomas Group LLC, a Delaware limited liability company (68% owned) Diaman-Mexo, S.A. De C.V., a Mexican corporation Fibre Light U.S. LLC, a Delaware limited liability company (80% owned) Genlyte Thomas Exports Inc., a Barbados corporation Genlyte Thomas Group Nova Scotia ULC, a Nova Scotian unlimited liability company GTG International Acquisitions LP, a Canadian limited partnership Lumec Holding Corp., a Canadian corporation Lumec, Inc., a Canadian corporation Lumec-Schreder, Inc., a Canadian corporation (50% owned) Lightolier De Mexico, S.A. De C.V., a Mexican corporation Thomas De Mexico, S.A. De C.V., a Mexican corporation Thomas Schreder Co., a U.S. partnership (50% owned) Yamada Day-Brite, Ltd., a Japanese corporation (50% owned) Genlyte Canadian Holdings, Inc., a Kentucky corporation GTG Intangible Holdings, LLP, a Kentucky limited liability partnership (68% owned) Canlyte Inc., a Canadian corporation Ledalite Architectural Products LP, a Canadian limited partnership