Maternal body weight, skinfold thickness and circumference measurements were examined in 23 lactating women and 10 nonlactating women longitudinally from 1 week to 12 weeks postpartum. The dietary intakes of Korean lactating and nonlactating women were measured by 24-hour recall method and effects of maternal energy intake on body weight change were analyzed by Pearson correlation. The mean daily energy intake of breast-feeding(BF, n=12), combination of breast and formula-feeding (CF, n=11), and formula-feeding (FF, n=10) mothers were 1941kcal, 187kcal and 1727kcal, respectively. A significant decrease in weight was observed at all group. Weight losses at 12 weeks of postpartum in BF, CF and FF motheres were 3.18kg, 3.91kg and 5.15kg respectively. Weight losses increased as calorie intake decreased (${gamma}$2=0.3803, p<0.05). The skinfold thickness and circumferences on all regions were decreased significantly except triceps and upper arm circumferences. However, there were no significant differences between lactating and nonlactating women. Anthropometric measurements decreased at the trunk but not at the limbs. Weight change was significantly correlated with changes of the scores for proximal circumference (${gamma}$2=0.4999, p<0.05). There results suggest that lactation does not promete weight loss in well-nourished women and that the Korean RDA for energy in lactation may be too high.