In a prospective study of the natural course of rheumatoid elbow arthritis, 32 consecutive patients with definite or classical rheumatoid arthritis from a rheumatological out-patient clinic were followed for 5 years. Clinical, functional and radiographic outcome was evaluated. At follow-up, 47 elbows were available for reexamination. There was no difference between initial and follow-up examination regarding clinical and functional parameters. Eighteen elbows with initial radiographic Larsen stages 3-5 had longer disease duration, higher score for pain on motion, larger extension deficit and less pronation than 29 elbows with initial radiographic stages 0-2. There was, however, radiographic progression to a higher stage in one third of the elbows. Measurement of bone attrition on initial and follow-up radiographs of elbows with initial radiographic stages 3-5 also showed progression in one third of the elbows. The authors conclude that the radiographic progress of elbow joint destruction in rheumatoid arthritis is slow and that elbow joint destruction does not always give rise to pain. In one third of the elbows with radiographic stages 3-5 pain is, however, severe, and total elbow replacement may be indicated.