Xawery Dunikowski (1875-1964), an outstanding sculptor and educator concerned about the fate of his own works, which he affectionately called his children, decided to hand them over to the care of the Polish State. A jubilee exhibition of his work at the National Museum in Warsaw at the turn of 1948 and 1949 provided the reason for donating the works on display to the People's Army of Poland. This gift included 151 sculptures, 20 paintings and 25 drawings. In return, the Ministry of Culture and Art promised to give the artist the Warsaw Rabbit House as a studio, flat and museum for the works. However, it took so long to rebuild the Królikarnia, destroyed during the war, that it was not until the first anniversary of the artist's death that an exhibition of his works donated by Marian Spychalski on behalf of the People's Army of Poland was opened. The donation included: "the works and memorabilia of the Master of Polish Sculpture of the Builder of People's Poland Professor Xawery Dunikowski bequeathed by his last will as a gift to the people and the Polish State".

The Museum's collection was enriched in the following years by donations and gifts from institutions and private individuals (including Antoine Cierplikowski and the artist's daughter, Maria Xawery Dunikowska) and purchases. Currently, in addition to 108 paintings, 246 painting sketches and 380 drawings, the Museum's holdings include more than 500 sculptures from all periods of Xawery Dunikowski's oeuvre, from the terracotta Portrait of a Cousin and The Miser (both from 1896), made during his studies, to his sketches of a Polish Soldier from 1963 - the artist's last monumental work.