OBJECTIVE: To define sociodemographic characteristics, medical factors, knowledge, attitudes, and health-related behaviors that distinguish women with established diabetes who seek pre-conception care from those who seek care only after conception. RESEARCH DESIGN AND METHODS: A multicenter, case-control study of women with established diabetes making their first pre-conception visit (n = 57) or first prenatal visit without having received pre-conception care (n = 97). RESULTS: Pre-conception subjects were significantly more likely to be married (93 vs. 51%), living with their partners (93 vs. 60%), and employed (78 vs. 41%); to have higher levels of education (73% beyond high school vs. 41%) and income (86% > $20,000 vs. 60%); and to have insulin-dependent diabetes mellims (IDDM) (93 vs. 81%). Pre-conception subjects with IDDM were more likely to have discussed preconception care with their health care providers (98 vs. 51%) and to have been encouraged to get it (77 vs. 43%). In the prenatal group, only 24% of pregnancies were planned. Pre-conception patients were more knowledgeable about diabetes, perceived greater benefits of pre-conception care, and received more instrumental support. CONCLUSIONS: Only about one-third of women with established diabetes receive pre-conception care. Interventions must address prevention of unintended pregnancy. Providers must regard every visit with a diabetic woman as a pre-conception visit. Contraception must be explicitly discussed, and pregnancies should be planned. In counseling, the benefits of pre-conception care should be stressed and the support of families and friends should be elicited.