OBJECTIVE Despite its frequent occurrence, the etiology of constipation has remained poorly understood. The influence of widely accepted risk factors such as inadequate dietary fiber intake, immobility, insufficient fluid intake, and poor muscle tone is unclear. This study examined the geographic distribution of constipation among Medicare beneficiaries to identify potential environmental risk factors. METHODS All Medicare beneficiaries with a diagnosis of constipation were extracted from the total Health Care Financing Administration data file of 1987 and stratified by sex, race, and state of residence. The population of each state by sex, race, and age >65 yr served as the denominator to calculate sex- and race-specific morbidity rates. RESULTS A distinct geographic distribution was observed. When stratified by individual states, hospital discharges for constipation were more common in rural as compared with urban states. Constipation also appeared to be more common in northern and in poorer states. CONCLUSIONS The distinct geographic pattern of constipation suggests the influence of three global environmental factors: rural living, colder temperature, and lower socioeconomic status.