Women with gestational diabetes have a 50% risk of developing non-insulin-dependent diabetes mellitus within 10 years of delivery and thus constitute a well-defined target population for primary prevention. Current obstetric standards advocate universal screening of all pregnant women for gestational diabetes. Therefore, approximately half the reproductive-age United States population is screened for carbohydrate intolerance before the onset of overt disease. Continuation of dietary and behavioral changes initiated during pregnancy theoretically could delay or prevent progression to overt diabetes. We present an economic model of the health care dollars that could be saved by promoting postpartum life-style changes in women diagnosed with gestational diabetes. Assuming the incidence of diabetes could be reduced by 10, 25, or 50% in a national cohort of women with gestational diabetes, then 32, 140, or 331 million health care dollars could be saved over 10 years.