The pathologic spectrums of the tennis elbow are varies as lateral epicondylitis, degenerative partial tear of extensor tendon origin, annular ligament lesion, synovial fringe between radio-capitellar joint, bursitis and posterior interosseous nerve pathology. So it is difficult to perform separate treatments for each different pathologic conditions. Conservative treatments for the tennis elbow are consisted of rest, immobilization, non-steroidal anti-inflammatory drugs (NSAID), and local injection of the steroid. Usual success rates of the conservative treatment have been reported approximately more than 90%. Several methods of surgical treatm nt of the resistant tennis elbow have been reported. Authors performed surgical treatment for twelve cases of the resistant tennis elbow from Jan. 1989 to Jan. 1994. Authors modified the Nirschl's technique; flap retraction of the extensor carpi radilais brevis (ECRB) and common extensor tendon to expose the radio-capitellar joint and no reattachment of detached tendons to the lateral epicondyle and side-to-side suture with maximal stretching of the ECRB tendon. Identified pathologic conditions were the degenerative partial tear and friable granulation tissues at the ECRB origin, sclerosis of the lateral epicondyle (ten cases), synovial fringe bewteen the radio-capitellar joint (two cases). In one case, authors couldn't find any abnormal pathologic conditions. Microscopic examinations (two cases) showed angioblastic proliferation, fibrosis, degeneration of the collagen fiber. Among these patients, eleven patients were industrial worker (eight painter, two welder and one carpenter). They have something in common with using hammer mainly. The hammering might be a possible cause of the tennis elbow. After the surgery, the functional recoveries were satisfactory. The final results were four excellent (33.3%) and good (66.6%) by Nirsh & ettrone grading system. The time required to return to the original job were varied from one month to eight months (average 4.3 months).