The objective of this study was to estimate rates of and factors associated with postpartum diabetes testing in women with recent gestational diabetes mellitus (GDM). Secondary data analysis was conducted using data from the 2009 and 2010 Pregnancy Risk Assessment Monitoring System from three states and one city (Colorado, Minnesota, Utah, and New York City). Frequency of postpartum diabetes testing was estimated overall and among women who attended a postpartum visit. Multivariable logistic regression was used to determine factors associated with postpartum diabetes testing. Approximately 8.2% [95% confidence interval (CI) 7.5-8.9] of women self-reported a history of GDM (n = 829), of which 48.5% (43.9-53.1) reported being tested for diabetes postpartum. Among the 90.0% (86.5-93.4) of women with recent GDM who attended the postpartum visit, 51.7% (46.1-57.2) reported being tested for diabetes postpartum. Women who received inadequate/intermediate prenatal care were half as likely to report postpartum testing compared with women who received adequate prenatal care [odds ratio 0.45 (95% CI 0.25-0.83)]. Women with a prepregnancy body mass index classified as obese were over twice as likely to report postpartum testing compared to normal weight women. Women with GDM are at increased risk of persistent glucose intolerance after delivery, yet postpartum testing rates remain around 50%, regardless of attendance to the postpartum visit. Improving adequacy of prenatal care might further increase postpartum testing rates. Continued efforts to translate postpartum testing into practice are needed among these women at risk for future type 2 diabetes.