Of 3,563 consecutive obstetric patients undergoing glucose screening, 517 (14.5%) were found to have plasma values of greater than or equal to 140 mg%, and 74 (14.3%) of 517 were found to be diabetic on standard oral glucose tolerance testing, for an overall incidence of 2.1%. There was no absolute value on the glucose screen that predicted an abnormal oral glucose tolerance test. Twenty-eight of the 74 diabetics demonstrated none of the classic risk factors for glucose intolerance during pregnancy. Only when combining those patients over 30 years of age and with a mean body weight greater than 120% of the ideal body weight was statistical significance reached when that group was compared to the overall group. Thus, our data support the recommendation for universal prenatal glucose screening.