In aging hypopituitary dwarf mice (dwdw), articular chondrocytes are poorly supplied with organelles; aggregation of collagen in the cartilaginous matrix is decreased, and aging of the articular cartilage is retarded as compared to non-dwarf mice (Dwdw or DwDw) of the same strain. Osteoarthrosis developing in 58% of male and in 22 % of female non-dwarfs was not observed in dwarfs regardless of sex. The unusually long life span of dwarf mice suggests that in hypopituitarism aging of non-skeletal tissues is likewise retarded.