OBJECTIVE To assess the effects of dynamic exercise therapy in improving joint mobility, muscle strength, aerobic capacity and daily functioning in patients with rheumatoid arthritis (RA). In addition, possible unwanted effects such as an increase in pain, disease activity and radiological progression were studied. METHODS We searched the Cochrane Musculoskeletal trials register, the Cochrane Controlled trials Register, Medline, Embase and SCISEARCH databases up to may 1997 in order to controlled trials on the effect of exercise therapy. METHODS Randomized trials on the effect of dynamic exercise therapy in RA patients with an exercise program fulfilling the following criteria: a) intensity level such that heart rates exceeded 60% of maximal heart rate during at least 20 minutes, b) exercise frequency of two session per week, and c) duration of intervention of greater than six weeks METHODS Two blinded reviewers independently selected eligible studies, rated the methodological quality and extracted data. RESULTS Six out of 30 identified controlled trials met the inclusion criteria. Four of the six included studies fulfilled at least seven out of 10 methodological criteria. Due to heterogeneity in outcome measures, data could not be pooled. The results suggest that dynamic exercise therapy is effective at increasing aerobic capacity and muscle strength. No detrimental effects on disease activity and pain were observed. The effects of dynamic exercise therapy on functional ability and radiological progression are unclear. CONCLUSIONS Dynamic exercise therapy has a positive effect on physical capacity. Research on the long-term effect of dynamic exercise therapy on radiological progression and functional ability is needed.