OBJECTIVE: To evaluate the relationship of central fat distribution with gestational glucose tolerance during the usual time for screening gestational diabetes. RESEARCH DESIGN AND METHODS: This cross-sectional study investigated 1,113 consecutive women, ≥ 20 years old, pregnant for ∼ 21 to 28 weeks, without history of previous diabetes outside pregnancy, who attended two general prenatal care units in Porto Alegre, Brazil, from 1991 to 1993. Weight, height, waist and hip circumferences, and skinfolds were measured, and a 2-h, 75-g glucose tolerance test was performed. Data were analyzed using multiple linear regression models. RESULTS: Waist-to-hip ratio (WHR) and waist circumference were independently associated with higher 2-h glycemia. Glycemic level was 0.11 and 0.13 mmol/l greater for each standard deviation increase in WHR (0.06) and waist circumference (8.0 cm), respectively (P < 0.02). Restricting analyses to the subset of women with uterine height ≤ 26 cm improved the association (0.13 and 0.19 mmol/l, respectively, P < 0.02); differences of 0.22 and 0.19 mmol/l were observed for 1 SD changes in the sum of skinfold thicknesses (24.7 mm) and in age (5.5 years), respectively. CONCLUSIONS: Central fat distribution measured in pregnancy is an independent predictor of gestational glucose intolerance. This finding supports the concept that NIDDM and gestational diabetes are parts of the same disease, differing basically in their moment of detection. The usefulness of these anthropometric measurements in identifying pregnant women at high risk of having gestational glucose intolerance merits further investigation.