Experiments on adult rats showed that a single intravenous injection of antitumor drug vepeside in a MTD (maximum tolerable dose) reduced the reproductive status during periods corresponding to exposure of mature sex cells, spermatocytes, and spermatogonia in male rats and exposure of oocytes in ovulating, mature, and primordial follicles in female rats. Reduction of the male and female reproductive function manifested in increased antenatal mortality of the progeny. The toxic effects of the drug on mature male sex cells caused temporary partial infertility.