In recent years, homelessness has been recognized as a growing urban social problem in various countries throughout the world. The health problems of the homeless are considerable. The purpose of this study was to elicit, with sociodemographic profiles, the disease patterns among Tokyo's homeless. The subjects were 1,938 men who stayed at a welfare institution from 1992 to 1996. Diagnosed diseases/injuries and sociodemographic profiles were analyzed. The disease patterns of the homeless were compared to those of the male general population. Of the subjects, 8.3% were admitted to the hospital; 64.0% received outpatient care. Their observed morbidity rates by disease category were greater than those of the male general population in both Japan and Tokyo. Comorbidity of alcoholic psychosis/alcohol-dependent syndrome to both liver disease and pulmonary tuberculosis were greater than the average (P < .01). Construction work brought a higher risk of pulmonary tuberculosis (odds ratio = 2.0) and dorsopathies (odds ratio = 1.4) than did other jobs (P < .05). Disease patterns among the homeless in Tokyo were characterized by alcoholic psychosis/alcohol-dependence syndrome; liver disease; pulmonary tuberculosis; diabetes mellitus; fractures, dislocations, sprains, strains; hypertension; and cerebrovascular disease. Although the sociodemographic backgrounds of Tokyo's homeless have become more diverse, the principal occupation of the homeless was unskilled daily construction work, which underlay the characteristics of their disease patterns.