The effects of 22,25-diazocholesterol dihydrochloride (SC-12937) on the spermatogenesis of the bandicoot rat (Bandicota bengalensis), heretofore unreported on any mammalian species, were studied. Rats were given a single subcutaneous injection of SC-12937 at a dosage of 100 or 200 mg/kg body weight and were killed on days 2 or 10 post-injection. Quantitative analysis of the germinal epithelium was performed on testicular sections (5 μm) stained with periodic acid-Schiff-hematoxylin to assess spermatogenesis. Treatment with SC-12937 at both dosages was found to interfere with the spermatogenic process of this pest rat. In addition to its antispermatogenic action, at higher dosage (200 mg/kg), this compound produced a marked suppression in accessory organ function. The results indicate that a single administration of SC-12937 in low dosage can cause spermatogenic inhibition without affecting accessory organ function in the bandicoot rat.