OBJECTIVES: The aim of this study was to assess the prevalence and associations between anal intercourse and fecal incontinence. METHODS: Analyses were based on data from 6,150 adults (≥20 years) from the 2009-2010 cycle of the National Health and Nutrition Examination Surveys. Fecal incontinence was defined as the loss of liquid, solid, or mucus stool occurring at least monthly on a validated questionnaire. A gender-specific sexual behavior questionnaire assessed any anal intercourse via an audio computer-assisted personal interview. Co-variables included: age, race, education, poverty income ratio, body mass index, chronic illnesses, depression, loose stool consistency (Bristol Stool Scale types 6 or 7), and reproductive variables in women. Prevalence estimates and prevalence odds ratios (PORs) were analyzed in adjusted multivariable models using appropriate sampling weights. RESULTS: Overall, 4,170 adults aged 20-69 years (2,070 women and 2,100 men) completed sexual behavior questionnaires and responded to fecal incontinence questions. Anal intercourse was higher among women (37.3%) than men (4.5%), P<0.001. Fecal incontinence rates were higher among women (9.9 vs. 7.4%, P=0.05) and men (11.6 vs. 5.3%, P=0.03) reporting anal intercourse compared with those not reporting anal intercourse. After multivariable adjustment for other factors associated with fecal incontinence, anal intercourse remained a predictor of fecal incontinence among women (POR: 1.5; 95% confidence interval (CI): 1.0-2.0) and men (POR: 2.8; 95% CI: 1.6-5.0). CONCLUSIONS: The findings support the assessment of anal intercourse as a factor contributing to fecal incontinence in adults, especially among men.