The effect of soft-laser therapy on rheumatoid arthritis was evaluated in 17 patients with symmetrical involvement of the metacarpophalangeal joint of the index. Nine treatments with a He-Ne laser, 6 J/cm2, were given on the one hand with a sham irradiation of the other. The study was double-blind. The laser therapy gave some pain relief, but no difference in morning stiffness or joint performance was obtained. It is concluded that the laser therapy is of limited value in rheumatoid arthritis.