Theodore Roosevelt's death at age 60 was probably caused by a pulmonary embolus, but it was preceded by a 2 1/2-month illness described as inflammatory rheumatism. He had intermittent fever and acute arthritis in several joints leading to hospitalization and enforced bed rest for 6 weeks. The details of his illness and its possible etiology are reviewed. Inflammatory rheumatism was a descriptive term within which several modern diagnoses might be included. Although it is not possible to identify Roosevelt's illness with any certainty, it was most compatible with polyarticular gout, although reactive arthritis, rheumatic fever, and several other diagnoses cannot be ruled out.