OBJECTIVE: To assess the validity of White's classification, including the role of chronic hypertension, in a contemporary diabetic population. METHODS: We performed a retrospective cohort study of all singleton pregnancies with pre-existing diabetes mellitus from 2008 to 2013. Adverse outcomes were compared across classes B, C, D, and vascular disease (R, F, H) and further stratified by the presence or absence of chronic hypertension. Outcomes examined were a composite perinatal outcome (stillbirth, neonatal death, shoulder dystocia, birth injury, seizures, requiring chest compressions or intubation at delivery, blood pressure support), small for gestational age (SGA), large for gestational age (LGA), macrosomia, shoulder dystocia, preterm delivery at less than 37 weeks of gestation, preeclampsia, and cesarean delivery. RESULTS: Of the 475 patients, the 1980 White's classification was significantly associated with SGA, LGA, macrosomia, preterm delivery, preeclampsia, and cesarean delivery (P≤.01). Within each White's class based on age or time since diagnosis alone, hypertension was significantly associated with a higher incidence of preeclampsia in class B (16% without hypertension compared with 32% with hypertension, P<.01) and C (22% compared with 40%, P.04), SGA in C (4.7% compared with 21%, P<.01), preterm delivery in B (25% compared with 46%, P<.01) and C (35% compared with 58%, P.01), and the composite neonatal outcome in B (7.9% compared with 17%, P.03). The incidence of adverse outcomes in classes B and C with hypertension resembles the incidence of adverse outcomes in those with diabetes one class higher. CONCLUSION: The 1980 White's classification system, taking into consideration the presence of chronic hypertension, remains a useful system for counseling pregestational diabetic women regarding adverse pregnancy outcomes.