The lipids in the epithelium of seminal vesicles of 11 adult bulls were studied by means of histochemical methods and thin layer chromatography. In the large basal lipid vacuoles dominate cholesterol, esters of cholesterol and tryglycerides. Phosphatides are also present in the large basal lipid vacuoles as well as in the smaller apical lipid droplets of the columnar cells. The existence of alkyl diglycerides, neutral plasmalogens and methyl esters of fatty acids, proved by 2-dimensional chromatography, can be taken as evidence that fatty acids, cholesterol, triglycerides and phosphatides are synthesized within the seminal vesicle epithelial cells. Free fatty acids as well as those incorporated in mono-, di-, triglycerides and polar lipids of the seminal vesicle epithelium are predominantly unsaturated, thus pointing to rapid mobilization and turnover of their esters. The cholesterol in the basal lipid vacuoles of bovine seminal vesicle is possibly eliminated from the epithelium via the subepithelial capillaries for there is no evidence of lipid secretion into the glandular lumen nor of a continued steroid synthesis from cholesterol within the seminal vesicle.