To investigate the pathogenesis of sterility in men with varicocele and summarize the effects of combined treatment, we anallyed ultrastructure of testicular specimens in 21 cases. With combined surgical and medicinal treatment, 16 men (76.2%) made their wives pregnant during a period of 2 years after the operation. Electron microscopy disclosed glycogen infiltration of sertoli cells, and decreased spermatogenesis especially involving the middle and late stages. Defective carbohydrate and energy metabolism in the testis is suggested as the key point in the pathogenesis of sterility, and a combined surgical and medicinal treatment is beneficial to the increase of pregnant rate.