EXHIBIT 21 Subsidiaries of the Registrant There are no parents of the Registrant, Walgreen Co. (an Illinois corporation). The following subsidiaries are wholly owned by the Registrant, 15 of which are engaged in the operation of retail drug stores and one, Walgreens Healthcare Plus, Inc., in mail order drug operations. STATE, COMMONWEALTH OR NAME COUNTRY OF INCORPORATION Walgreen Arizona Drug Co. Arizona Bond Drug Company of Clinton Delaware Bond Drug Company of Illinois Illinois Walgreens Healthcare Plus, Inc. Illinois Walgreen Southgate Corp. Indiana Walgreen Woodmar, Inc. Indiana Walgreen Louisiana Co., Inc. Louisiana Walgreen Columbus Co. Nebraska Walgreen Fremont Co. Nebraska Walgreen Hastings Co. Nebraska Walgreen Kearney Co. Nebraska Walgreen Lincoln Co. Nebraska Walgreen Eastern Co., Inc. New York Walgreen New Berlin, Inc. Wisconsin Walgreen of Puerto Rico, Inc. Puerto Rico Walgreen of San Patricio, Inc. Puerto Rico In addition to the above named subsidiaries, the Registrant wholly owns 7 subsidiaries engaged in service or real estate operations, and 16 inactive subsidiaries. These 23 subsidiaries, considered in the aggregate as a single subsidiary, would not constitute a significant subsidiary. All wholly owned subsidiaries are included in the consolidated financial statements.