Flexor tenosynovitis (FT) is a common manifestation of rheumatoid arthritis (RA), contributing to hand deformity and manual dysfunction. The efficacy of intratendon sheath corticosteroids was assessed by reviewing the results of such treatment in 173 episodes of FT documented in 46 patients with definite or classic RA. Ninety-three percent of initial episodes resolved completely for 3 or more months (median: 25 months); tenosynovitis did not recur in 59%. The likelihood of a favorable response did not diminish with treatment of recurrent FT in a given digit. Comparable results were found in 52 FT episodes observed in 38 non-RA patients. No tendon sheath or soft tissue infection or tendon rupture ensued in either treatment group. The response was influenced by the specific corticosteroid preparation selected. Based on this experience, a trial of intratendon sheath corticosteroid injections prior to surgical intervention is recommended for RA patients with FT.