A population survey was carried out in Stockholm during the period 1965-67 for the purpose of determining the prevalence of rheumatoid arthritis (RA). 239 subjects with RA were found in a random sample of 15,268. In 1983, 17 years later, all the 127 persons still living could be traced, 109 of whom were re-examined. In 95, all the information required to satisfy the New York diagnostic criteria was available, i.e. with radiographs of the hands and feet and a Waaler-Rose test. The number of subjects with involvement of at least 3 joints (criterion No. 2) had decreased from 72 to 36, while the persons with a positive Waaler-Rose test (criterion No. 3) had increased from 9 to 18. The total number of fulfilled criteria showed a reduction from a median of 2 criteria to 1. The Steinbrocker functional class remained unchanged for the group as a whole (median Class 2), with a significant deterioration only in the oldest age-group (from 2 to 3). The knee was most often the single joint in which the disease had started and also the joint which caused the subjects the most inconvenience at the follow-up. Medical records were traced for 85 of the 112 who had died. Among them, 44 cases of RA or polyarthritis were noted. The present study gives a conception of RA in the population, as well as of its development over a long span of time.