The lipid composition of human testis in testicular and post-testicular causes of infertility was studied. The testicular causes of infertility was represented by patients with adult seminiferous tubule failure and Klinefelter’s syndrome. The post-testicular causes of infertility were represented by patients with obstruction of efferent ducts of testes. A significant accumulation of total testicular lipids was observed in both causes of infertility. A marked increase in free and esterified cholesterol, monoglycerides and triglycerides caused the accumulation of total testicular lipids in testicular causes of infertility. The accumulation of these lipids was more pronounced in Klinefelter’s syndrome compared to adult seminiferous tubule failure. In post-testicular causes of infertility, a very marked increase in phospholipids along with cholesterol fractions and glycerides led to the accumulation of total testicular lipids. The significant increase in total phospholipids caused by the increases in phosphatidylcholine and phosphatidylethanolamine differentiates post-testicular causes of infertility from testicular causes in which phospholipid classes remained unaffected. Thus, changes in hormonal mileu due to pathological conditions also lead to marked alterations in testicular lipids.