The aim of the present work was to assess the prevalence of anal incontinence in the elderly population attended in the "Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo". The method employed was of individual interviews with patient attended in the Geriatric Ambulatory. As part of the assessment patients were classified as to sex, age, color, social-economical class and education, and compared to available data on the elderly population of the State and the City of São Paulo. Besides the question on signs and symptoms related to anal incontinence, associated factors such as bowel habit, sensation of incomplete evacuation, urgency to evacuate and soiling were also analysed, as well as, factors possibly related to anal incontinence such as urinary incontinence, use of medication as laxatives, associated diseases, such as neurological affections and diabetes mellitus, number of child births, and assistance received, previous anorectal or perineals operations, and locomotions limiting factor. The statistical method of test of proportion was used to analyse the proportions of the populations interviewed, as to sex and literacy compared to the elderly population of the State and City of São Paulo. To analyse the social-economical class of the population interviewed compared to the elderly population economically and non economically active, of the State of São Paulo, the test of qui-square adjusted was used. The test of qui-square was used to verify if the population of incontinent and continent, by sex; incontinent and continent in relation to bowel habit, by sex; incontinence sufferer of continuous and descontinuous anal incontinence, by sex; incontinent sufferer of anal incontinence to gas, liquid or solid, and the association of these manifestations, by sex; patients who complained of soiling, by sex; incontinent and continent, previously submitted to anorectal or perineal operations; and continent and incontinent with diabetes mellitus, are equal. To verify the proportions of women who had vaginal delivery in the continent and incontinent group, the test of Mann-Whitney was used. One hundred fourty six patients were interviewed, 43 men of an average 75 years old (62 to 91) and 103 women of an average 72 years old (60 to 88); as to colours, 69.9% were white, 18.5% were mullato, 9.6% were black and 2% were yellow. The comparative analysis with populational data indicated that the population interviewed was representative of the elderly population of the State and the City of São Paulo, as to age, color, social-economical class and education. The prevalence of anal incontinence was of 10.9% with no difference between the sexes, intestinal obstipation referred by 15.4% of the men and 28.1% of the women, sensation of incomplete evacuation referred by 21.2% of the patients, and the association of both referred by 13.7% were the most frequently observed functional gastrointestinal alterations. Soiling was referred by 10.3% of the patients with no difference related to sex. The use of medication or laxatives, the presence of diabetes mellitus, neurological affections, previews anorectal or perineal operations, or locomotion limiting factors, have no relation to anal incontinence. The prevalence of urinary incontinence was of 30.1%, and double continence of 6.3% with no statistical difference between sexes. There was statistical evidence of association between childbearing and anal incontinence.