OBJECTIVE: The purpose of this study was to determine the frequency of recurrent gestational diabetes mellitus (GDM) and to find risk factors that can predict the recurrence of GDM in Korean women with previous GDM. RESEARCH DESIGN AND METHODS: We evaluated women who had GDM in an index pregnancy (1993-2001) and a subsequent pregnancy by 2003. An oral glucose tolerance test (OGTT) was performed during the index pregnancy and 2 months postpartum. The recurrence rate of GDM was assessed among 111 women who had a subsequent pregnancy. Multivariate logistic regression analysis was used to identify independent predictors of recurrent GDM. RESULTS: The frequency of recurrent GDM in subsequent pregnancies was 45.0% (95% CI 35.6-54.4%). Women with impaired fasting glucose and/or impaired glucose tolerance 2 months postpartum were at increased risk for recurrent GDM (relative risk 2.31, 95% CI 1.24-4.30). Higher BMI before the subsequent pregnancy (P = 0.024), higher fasting glucose concentration (P = 0.007) 2 months postpartum, and lower 1-h insulin concentration (P = 0.004) of the diagnostic OGTT in the index pregnancy were independent risk factors for recurrence of GDM in subsequent pregnancies. CONCLUSIONS: GDM recurred in nearly half of subsequent pregnancies in Korean women. Fasting glucose 2 months postpartum might be a clinically valuable predictor of recurrent GDM risk.