The composition and quantity of glycosphingolipids in kidney from 3-50-week-old male and female rats have been investigated. Glycosphingolipids were separated by high-performance liquid chromatography on a diethylaminoethyl-porous glass and porous glass column followed by high-performance thin-layer chromatography. The quantity of neutral glycolipids in male rat kidney decreased significantly between 3 and 25 weeks; the quantity in 25-week-old kidney became half the quantity found in 3-week-old kidney and remained constant thereafter. The quantity of neutral glycolipids in female rat kidney did not show age-dependent changes. The composition of neutral glycolipids revealed by high-performance thin-layer chromatography was constant, regardless of age and sex. Monoglycosylceramide and tetraglycosylceramide were the major compoments at all ages in both sexes. In contrast to the patterns of neutral glycolipids, ganglioside content was higher in female rats than males, and total ganglioside content increased in both sexes with increasing age. The most remarkable change was an increase of disialoganglioside in female rat kidney between 5 and 25 weeks. The ratio of disialogangliosides to monosialogangliosides (D/M value) in female rat kidney increased 4-fold during this period. The ganglioside pattern in female rat kidney was affected by spaying. The quantity of disialogangliosides decreased rapidly on the 7th day after spaying, but the level went back to normal on the 14th day after spaying. The data strongly suggest that sex hormones influence glycosphingolipid synthesis in rat kidney.