Congenital anomalies are more common in the offspring of women with type 1 and type 2 diabetes mellitus. Herein we define those anomalies more commonly found in the offspring of women with diabetes mellitus, and examine the role of hyperglycemia in their pathogenesis. We then discuss methods for the optimal screening and detection of embryopathy. We conclude by presenting evidence in support of preconception diabetes care to lower the risk of fetal anomalies in women with diabetes mellitus.