Groups of male Long‐Evans rats 30, 50, or 70 d old were injected subcutaneously (sc) with a single dose of 0, 5.5, 11.5, or 24.6 μmol Cd/kg as cadmium chloride. All animals were killed 60 d after treatment. At 2 h prior to sacrifice, the rats were injected sc with 100 IU human chorionic gonadotrophin (hCG) to maximally stimulate serum testosterone concentrations. After sacrifice the testes, epididymides and seminal vesicles were removed and weighed. Cardiac blood was taken, and serum concentrations of testosterone (sT) and follicle‐stimulating hormone (sFSH) were determined. Sperm concentration in luminal fluid collected from the vas deferens was determined.