A mortality study was performed on all patients treated in hospitals in Stockholm County who were diagnosed during 1971 as having rheumatoid arthritis. The group consisted of 1165 patients. They were followed up through 1978. The mortality was about 2.5 times higher than for the general Stockholm population, and the females had the highest excess mortality. The excess mortality was particularly high in cases of infection, and of gastrointestinal, urogenital and rheumatic disease. The mortality in cancer was no different from that of the general population, and there was also no excess mortality regarding any particular site or type of cancer. 20% of the deceased had RA as the underlying cause of death and 18% as contributory cause of death.