Women contraceptive progestogen (Levonorgestrel) was evaluated as chemosterliant for laboratory & domestic collected female rats in 4 ascending doses as 5.40 jtg/rat/day (10 times of rat contraceptive therapeutic doses), 10.8, 16.2 & 21.6 pg/rat/day (as, 20, 30 and 40 time of the rat dose) respectively. These doses were administered for female rats via paraffin bait at a concentration of 154g, 308ug, 462ug & 616,12 Levonorgestrel /kg paraffin block during one month. A direct relationship was recorded between the increase in the administered dose and the increase in mean body weight at the end of exposure period. No adverse effect could be recorded in the total or differential leucocytic count of treated groups in comparison with the control rats. The used progestogen causes irreversible changes leading to sterility of the exposed female, which is increased with increasing the dose. Atrophy of the ovaries and fibrosis of the endometrium was observed in histological sections after administration to the doses of 16.2 & 21.6 tg/rat/day. While three offsprings were produced after mating of two females treated with16.2 pig/rat/day, no pregnancy could be recorded in domestic and laboratory females treated with 21.6 jig/rat/day. This clarified the efficacy of progestogen derivative as an efficient chemosterilant inducing irreversible Sterility in the exposed rats. Levonorgestrel is palatable to rats, also considered as safe for human being and effective approach to regulation of rodent populations as well as to curb rodent numbers.