Patients with rheumatoid arthritis (RA), 500 males and 500 females, aged 40 years and over, together with an age and sex matched control population, were observed over a 10-year period. The overall mortality was significantly higher in both men and women with RA than in the controls. During the followup, 42 patients with RA (28 males, 14 females) and 58 control subjects (36 males, 22 females) died from malignant neoplasms, but this difference was not statistically significant. A significant excess of deaths from neoplasms of the hematopoietic system was observed in patients with RA. Subjects without RA had significantly higher mortality rate from cancer of gastrointestinal origin than patients with RA.