We sought to evaluate the likelihood of recurrent diabetes in women with a prior history of diet-treated (class A gestational diabetes mellitus (GDM). In a retrospective cohort analysis, nulliparous women diagnosed based upon National Diabetes Data Group criteria with diet-treated GDM who had recurrent diabetes in a subsequent pregnancy were compared with those who did not have recurrent diabetes. The probability of recurrent diabetes was calculated using maternal age at first pregnancy, interpregnancy interval, and body mass index (BMI) during the subsequent pregnancy. Three hundred forty-four nulliparous women with diet-treated GDM had a subsequent delivery in our database. One hundred thirty-seven (40%) had recurrent diabetes. Women with a history of GDM were more likely to have recurrent diabetes if they were heavier (193 versus 173 lbs; p<0.001; BMI 35.7 versus 32.2; p<0.001) and waited longer between pregnancies (2.9 versus 2.4 years, p=0.02). Age, interpregnancy interval, and BMI can be used to predict diabetes recurrence in pregnant women with a history of GDM.