This experiment was conducted to investgate the effect of dietary protein and energy levels during gestation and lactating period on the reproductive performances of gravid swine. Fifty-four crossed sows (Landrace × Large White) which were about at 28 days in pregnancy were used in the feeding trials for a period of 17 weeks. The experimental treatment was divided into 9 groups combining 3 levels of dietary protein (CP 15-16%, 13-14%, 11-12%) and energy level (DE 3.6000kal/kg, 3,400kcal/kg, 3,200kcal/kg) during gestation and lactation periods. During 80 days after mating all sows received their own experimental diet 2.0kg per head daily, and during 5 weeks of late period of gestation received 2.3kg per daily and all sows were fed ad libitum during lactation period the same diets supplied during late pregnant period. The results obtained are summarized as follows: 1. Body weight of sows increased during gestation and decreased during lactation period, but there were no significant effects on the protein and energy fed during gestation and lactation period. The rebreeding rate for sows fed a low protein and energy diets during gestation and lactation period was lower than for sows fed high and medium level of dietary protein and energy. 2. There were no differences in digestibilities of dry matter and total carbohydrate, but the digestibility of crude protein decreased as protein level during gestation period