We investigated the association between self-reported constipation and several demographic and dietary variables in 15,014 men and women 12-74 years of age examined between 1971-75 during the first Health and Nutrition Examination Survey. Overall, 12.8 percent reported constipation. Self-reported constipation correlated poorly with stool frequency. Nine percent of those with daily stools and 30.6 percent of those with four to six stools/week, reported constipation. Constipation was more frequent in Blacks (17.3 percent), women (18.2 percent), and those over age 60 (23.3 percent); after adjusting for age, sex, and race it was more prevalent in those with daily inactivity, little leisure exercise, low income, and poor education. Constipated subjects reported lower consumption of cheese, dry beans and peas, milk, meat and poultry, beverages (sweetened, carbonated and noncarbonated), and fruits and vegetables. They reported higher consumption of coffee or tea. They consumed fewer total calories even after controlling for body mass and exercise.