Pulsed electromagnetic fields (PEMF) have been shown to be beneficial in the treatment of rotator cuff tendinitis. As lateral humeral epicondylitis (tennis elbow) is a similar chronic tendon lesion, 30 patients with both clinical and thermographic evidence of tennis elbow were randomly allocated to receive either active or inactive PEMF therapy. Treatment was continued for a minimum period of eight weeks. At this time there was no statistical difference between the two groups.