Objective:To identify the optimal gestational age (GA) for induction of labor (IOL) at term among patients with gestational diabetes (GDMA) according to perinatal outcomes.Study Design:The US Natality Database from 2007 to 2010 was reviewed. Inclusion criteria were singleton delivery, IOL at 37 to 42 weeks and GDMA. Exclusion criteria included congenital anomalies, pre-gestational diabetes, hypertensive disorders, previous cesarean, breech presentation and rupture of membranes. Controls were non-GDMA cases delivered in geographic and temporal proximity. Delivery mode, macrosomia and perinatal complications were analyzed. Logistic regression adjusted for confounders was used to calculate odds ratios by GA using 39 weeks non-GDMA as reference.Results:In all, 96 964 cases and 176 079 controls were included. Increased risk for all adverse outcomes among GDMA cases was found. The nadir for intrapartum and neonatal complications was 38 and 40 weeks, respectively, whereas for cesarean and macrosomia was 39 weeks.Conclusion:The optimal timing for IOL at term in GDMA appears to be 39 to 40 weeks.