To ascertain current practice trends among obstetricians and maternal-fetal subspecialists regarding the care of pregnancies complicated by diabetes mellitus, a questionnaire was sent to all members of the Society of Perinatal Obstetricians (SPO) and a randomly selected group of American College of Obstetricians and Gynecologists (ACOG) Fellows. A total of 273 of 356 SPO members (77%) and 198 of 504 ACOG Fellows (39%) responded. When divided according to years post-residency (ACOGa, less than 15 years; ACOGb, 15 years or more), significant differences in practice patterns were observed for ACOG Fellows. The SPO responses were similar among these subgroups. Despite current ACOG recommendations, most clinicians practice universal screening for gestational diabetes. Significant discrepancies appear to exist between ACOGb versus ACOGa and SPO with regard to methods of glucose surveillance and the threshold for initiating insulin therapy in gestational diabetes. Intensive fetal surveillance, elective delivery, and high cesarean rates are common in pregnancies complicated by insulin-dependent diabetes mellitus, which is most often managed by a perinatologist or by an obstetrician in consultation with an internist. Few insulin-dependent patients seek preconceptional care.