OBJECTIVE This analysis was focused on 1-year maternal and infant follow-up of a randomized trial that tested a weight management intervention conducted during pregnancy. METHODS One hundred fourteen women with obesity (mean BMI 36.7 kg/m(2) ) were randomly assigned at a mean of 15 weeks gestation to a weight management intervention or usual care control condition. The intervention ended at delivery and resulted in less gestational weight gain and a lower proportion of large-for-gestational-age newborns among intervention compared with control participants. The primary outcome at 12 months postpartum was maternal weight. Secondary outcomes included infant weight-for-age and weight-for-length z-scores. RESULTS At 1 year, mothers in the intervention group weighed 96.3 ± 18.6 kg and those in the control group 99.7 ± 19.2 kg. There was no significant difference between groups in change in weight from randomization to 1 year postpartum (b = -0.47, 95% CI: -4.03 to 3.08). There was a significant main effect of group for infant weight-for-age z-scores (b = -0.40, 95% CI: -0.75 to -0.05) but not infant weight-for-length z-scores (b = -0.20, 95% CI: -0.59 to 0.20). CONCLUSIONS A gestational weight management intervention did not influence maternal weight or infant weight-for-length at 1 year postpartum. Future studies may be warranted to determine whether extending prenatal interventions into the postpartum period would be beneficial for maternal and infant outcomes.