Ninety-two gilts averaging 110 kg. were used in two experiments conducted at two locations to determine the effects of level of feed intake (energy) during pregnancy on reproductive performance, development of offspring, and carcass characteristics and composition of lean tissue. One-half of the gilts was individually fed 1.36 kg. per head daily of a 24.5% protein diet while the remaining one-half was fed 2.27 kg. per head daily of a 15.1% protein diet during pregnancy. Fifty-nine gilts and their litters were continued through a 21-day lactation period during which one-half of the gilts from each gestation treatment was fed a 16% protein diet ad libitum while the remaining one-half of the gilts was fed the same diet to scale. Twenty-two litter units produced by gilts assigned to each gestation treatment were continued through the growing period subsequent to 21 days. Feeding 1.36 vs. 2.27 kg. feed (approximately 4,400 vs. 7,300 kcal. ME) per gilt daily during gestation resulted in significant reductions in daily gains (0.25 vs. 0.52 kg.), condition of gilts at parturition, total pigs farrowed per litter (8.5 vs. 9.7) and birth-weight of offspring (1.38 vs. 1.48 kg.). However, number of live pigs per litter (8.5 vs.9.5) and vigor of pigs at birth were not significantly affected by feeding level during gestation. Pigs from gilts fed at the lesser level of feed intake during pregnancy weighed significantly (5.1 vs. 5.9 kg.) less at 21 days and gained significantly more efficiently (feed/gain ratios of 1.84 vs. 1.95) during the period from 21 days to about 22.7 kilograms. Level of feed intake of the dam during pregnancy did not significantly affect rate of gain during the growing period subsequent to 21 days, feed/gain ratio subsequent to 22.7 kg., dressing percent, cross-sectional area of the l. dorsi, percent trimmed ham and loin of slaughter weight or of chilled carcass, or percentages of dry matter, protein and ether extract in the lean tissue. However, backfat thickness was significantly (P<.05) increased (3.86 vs. 3.65 cm.) in offspring from gilts fed 1.36 kg. per head daily during pregnancy. Feeding sows to scale vs. ad libitum during the 21-day lactation resulted in a significant decrease in feed consumption (76.8 vs. 97.0 kg.) accompanied by increased weight loss (15.0 vs. 5.6 kg.). Gilts fed at the lesser level of feed intake during pregnancy lost significantly less weight (3.9 vs. 15.6 kg.) during lactation than gilts receiving the greater quantity of feed during gestation. They also consumed more feed (101.5 vs. 93.0 kg.) when fed ad libitum during the 21-day lactation than gilts given the greater amount of energy during pregnancy. Feed intake of sows during lactation did not influence 21-day weights of pigs, rate and efficiency of gain during the growing period subsequent to 21 days, carcass length, backfat thickness, cross-sectional area of the l. dorsi, percent trimmed ham and loin of slaughter weight or of chilled carcass, and percentages dry matter, protein and ether extract in the lean tissue.