Anthropometric factors have been associated with colorectal cancer and adenomas but with conflicting results in women or regarding adenoma characteristics. The authors aimed to explore associations between anthropometric factors (height, weight, body mass index, waist and hip circumferences, and weight changes) and adenoma risk. They analyzed the 17,391 women of the French Etude épidémiologique des femmes de la Mutuelle Générale de l'Education Nationale (E3N)-European Prospective Investigation into Cancer and Nutrition (EPIC) cohort who underwent a colonoscopy during follow-up (1993-2002), including 1,408 who developed a first colorectal adenoma. In Cox multivariate proportional hazard regression models, obesity was associated with an increased colorectal adenoma risk (hazard ratio = 1.53, 95% confidence interval: 1.21, 1.94). This association was restricted to left colon adenomas (P(homogeneity) = 0.05 and 0.01 for colon vs. rectum and right vs. left colon, respectively), with a dose-effect relation observed from 22 kg/m². A high waist circumference was also associated with left colon adenoma risk (hazard ratio = 1.81, 95% confidence interval: 1.36, 2.41). Mean weight gain over 0.5 kg/year was associated with a 23% increased colorectal adenoma risk. Associations did not differ between advanced and nonadvanced adenomas. In conclusion, study findings suggest that obesity and weight gain are associated with early colorectal carcinogenesis in women, and specifically regarding the distal colon.