The relationship of diabetes knowledge to regimen compliance and metabolic control was examined in a sample of pregnant women with preexisting insulin-dependent and noninsulin-dependent diabetes mellitus (N = 27) and women who developed gestational diabetes during pregnancy (N = 45). Subjects completed self-report measures of diabetes knowledge and compliance with their diabetic regimen and blood glucose levels were monitored. Knowledge was positively, although modestly, related to dietary compliance, compliance with insulin administration and insulin reaction management recommendations, as well as fasting blood glucose levels. Findings suggest that among pregnant women, efforts to increase knowledge of diabetes specific to pregnancy may result in some improvement in selected aspects of the diabetic regimen.