In a prospective study the grip strength was measured preoperatively in 17 patients with chronic tennis elbow and postoperatively after a minimum follow-up of 1 year. The grip strength measured with a flexed and extended elbow was significantly less on the involved side (28.4 and 17.2 kg) than on the normal side (36.4 and 36.5 kg) ; postoperatively it increased significantly (33.9 and 34.2 kg) and almost reached the level of the normal contralateral side. An increase of grip strength measured with an extended elbow was correlated significantly with a satisfactory clinical outcome.