The research hypothesis assumed that the size of the cage affects bodyweight after weaning and prior to slaughter and, as a consequence, mean daily bodyweight gains in individuals of both sexes. The study was conducted from 2014 to 2015 at one of the private mink farms in Poland. In total, 800 brown mink were used as the object of research (400 animals in a given year). In each year, the animals were divided into two equal-sized groups, in accordance with their housing system. The first group included animals living in single-storey cages and the second group lived in two-storey cages (i.e. cages with an upper level added). The animals were weighed after weaning and before slaughter. Based on these data the mean daily bodyweight gains were calculated. The research hypothesis was rejected. The conclusion of the analysis of variance is the statement that the cage size did not affect either the animals' bodyweight or their mean daily weight gains. The differences in these results, however, were observed in individuals of different sexes. Males were significantly heavier than females and showed higher daily weight gains. High and positive correlation coefficients were also noticed between bodyweight prior to slaughter and mean daily weight gains. ______________________________________________________________________________________