日本財団
Hosokawa lives in Yugawara, Kanagawa. His wife, Kayoko Hosokawa, to whom he has been married since 23 October 1971, served as honorary chair of the Special Olympics Nippon Foundation and headed NPOs devoted to providing vaccines to children in developing nations and helping the intellectually disabled. He and Kayoko have three children: Morimitsu, Satoko and Yūko.