Chronic renal failure was induced in 3-month-old male rats by 5/6 nephrectomy. Potency and fertility studies were performed after 3 months of chronic uremia. The mean serum testosterone at the end of the experiments was significantly lower: 0.96±0.14 ng/mL compared to a control group of sham-operated male rats, 2.86±0.59 ng/mL,p<. 001. All the uremic male rats had normal accessory gland weights at the end of the study. Fertility and, in most animals, sexual behavior and mating were not different from the normal control group. It is concluded that in 5/6-nephrectomized uremic male rats, in spite of low testosterone level, fertility and reproductive system are maintained similar to normal control male rats.