The authors studied data on psychiatric disorders and eight chronic medical conditions in a community sample of 2,554 persons. The sex- and age-adjusted prevalence of any psychiatric disorder in the preceding 6 months was 24.7% and of lifetime psychiatric disorder was 42.2% among persons with one or more medical conditions, compared to 17.5% and 33.0%, respectively, for persons with no medical condition. Persons with chronic medical conditions were more likely to have lifetime substance use disorders and recent affective and anxiety disorders. Arthritis, cancer, lung disease, neurological disorder, heart disease, and physical handicap were strongly associated with psychiatric disorders, but hypertension and diabetes were not.