The article presents a Polish military physician whom the Doctors’ Retirement House in Warsaw is named after. Kazimierz Rudolf Fritz was born in Drohobych, on March 11, 1896. In 1916, he graduated from a renowned gymnasium in his hometown. In November 1918, as a cadet he participated in the defense of Lviv, the battle between the Polish inhabitants of the city (mostly gymnasium and university students) and Ukrainian soldiers of Dmytro Vitovsky who staged a coup d’etat. In 1925, he graduated from the Faculty of Medicine at Jan Kazimierz University in Lviv. In the interwar period he served in several military hospitals. Since 1936 he was a head of the dermatological ward in the 7th Regional Hospital in Poznań. During the German occupation he worked at the Ujazdowski Hospital and as a doctor of this institution he took part in the Warsaw Uprising in 1944. After the end of World War II, he headed the dermatological ward at the City Hospital in Chorzów. Doctor Fritz was the originator and one of the founders of the Doctors’ Retirement House in Warsaw. He died on November 9, 1979, at the age 83.