Objectives: To compare rates of postpartum care and contraception provided to women with gestational or preconception diabetes mellitus to women with no known diabetes mellitus. Methods: A retrospective cohort study of 199,860 women aged 15-44 years who were continuously enrolled in California's Medicaid program, Medi-Cal, from 43 days prior to 99 days after delivering in 2012. Claims for postpartum clinic visits and contraceptive supplies were compared for 11,494 mothers with preconception diabetes, 17,970 mothers with gestational diabetes, and 170,396 mothers without diabetes. Multivariable logistic regression was used to control for maternal age, race/ethnicity, primary language, residence in a primary care shortage area, state-funded healthcare program and Cesarean delivery, when examining the effects of diabetes on postpartum care and contraception. Results: Although postpartum clinic visits were more common with diabetes (55% preconception, 55% gestational, 48% no diabetes, p=b.0001), almost half did not receive any postpartum care within 99 days of delivery. Women with pregnancies complicated by diabetes were more likely to receive permanent contraception than women without diabetes (preconception diabetes, aOR: 1.39, 95% CI: 1.31-1.47; gestational diabetes, aOR: 1.20, 95% CI: 1.14-1.27). However, among women without permanent contraception, less than half received any reversible contraception within 99 days of delivery (44% preconception, 43% gestational, 43% no diabetes) and less effective, barrier contraceptives were more commonly provided to women with preconception diabetes than women without diabetes (aOR: 1.24, 95% CI:1.16-1.33). Conclusions: Low-income Californian women with pregnancies complicated by diabetes do not consistently receive postpartum care or contraception that may prevent complication of future pregnancies. Implications: Efforts are needed to improve rates of provision of postpartum care and high quality contraceptive services to low income women in California, particularly following pregnancies complicated by diabetes.