This experiment was carried out to study the efficacy of the exogenous indomethacin for prolongation of parturition in white rats. Sixty of the pregnant white rats used were injected with indomethacin. The survival rate of newborn, the administration time and the amount of dosage affecting on the prolongation parturition were investigated. The results obtained were as follows: 1. The average survival rates of newborn in groups injected with indomethacin on day 15, 17 and 19 of gestation were 78.2, 82.0 and 85.5%, respectively. There were no differences by the amount of dosage of indomethacin. 2. Mean gestation lengths of rats injected indomethacin on day 15, 17 and 19 of gestation were 23.39±0.18, 23.28±0.22 and 23.19±0.09 days, respectively. There were no significant differences (P$lt;0.05) among experimental groups. 3. For the amounts of dosage of 0.2㎎ × 1time, 0.4㎎ × 1time and 0.6㎎ × 1time per ㎏ per day the average intervals from injection to parturition were 22.98±0.05, 23.48±0.15 and 23.40±0.04 days, respectively. There were no significant differences (P$lt;0.05) among experimental groups.