Poor maternal nutrition during gestation can lead to intrauterine growth restriction resulting in offspring with low birth weight and altered organ development, negatively affecting production. We hypothesized that poor maternal nutrition during gestation would alter fetal body weight and organ mass of lambs during gestation. Western Whiteface ewes (n = 82) were bred to 1 of 4 rams and confirmed pregnant by ultrasound. Ewes were fed 100%, 60%, or 140% of NRC requirements for TDN beginning at d 30.2 ± 0.2 of gestation and offspring from these ewes will be referred to as CON, RES, and OVER, respectively. Fetal weights and organs were collected at d 45, 90, and 135 of gestation and within 24 h of birth. To date, organ weights have been collected from d 45 and 90. Data are expressed as percent of fetal weight and were analyzed using PROC MIXED in SAS. At d 45, fetal weight tended to be different (P = 0.067) between treatments with OVER offspring smaller than CON (P = 0.021) and RES intermediate (CON = 11.0 ± 0.6 g; RES = 10.1 ± 0.5 g; OVER = 9.2 ± 0.5 g). Liver weight at d 45 tended to be different (P = 0.055) with RES offspring larger than OVER (P = 0.017) and CON intermediate (CON = 6.7 ± 0.5%; RES = 7.6 ± 0.5%; OVER 6.1 ± 0.4%). We did not observe a difference in the weight of heart and kidney at d 45 (P ≥ 0.148). Although fetal weights were not different at d 90 (P = 0.329) liver weights were greater in OVER offspring vs CON and RES (P ≤ 0.05; CON = 5.5 ± 0.2%; RES = 5.7 ± 0.2%; OVER = 6.3 ± 0.2%). At 90 d an effect of maternal diet was not observed for kidney, heart, pancreas, adrenal, or renal fat weights (P ≥ 0.153). In conclusion, maternal under- and over-feeding affects liver development during early gestation, a period of rapid liver growth, which may lead to altered health and growth of the offspring later in life.