The Koizumi family has been prominent in Japanese politics since the early 1900s. Notable members of this family include:
Matajirō Koizumi (1865 - 1951) – Minister of Posts and Telecommunications, he was known as the "wild man" and "tattoo minister" because of a large dragon Irezumi tattoo on his back.Jun'ya Koizumi (1904 - 1969) – Son-in-law of Matajirō, he built a kamikaze airfield in 1944 at Kaseda, Kagoshima. Served as Director General of the Japanese Defense Agency.Tetsugoro Iryo (1924/5 - 1945) – nephew of Jun'ya and cousin of Junichirō Koizumi, died a kamikaze pilot.Junichirō Koizumi (1942 - ) – son of Jun'ya and grandson of Matajirō. Former Prime Minister of Japan.Kayoko Miyamoto (1957? - ) – ex-wife of Junichirō Koizumi.Kotaro Koizumi (1978 - ) – actor, eldest son of Junichirō.Shinjirō Koizumi (1981 - ) – politician, second son of Junichirō.Yoshinaga Miyamoto (1982 - ) – third son of Junichirō, has never met his father.