The purpose of this study was to see if autologous blood injection ia as efficacious as steroid injection in the treatment lateral epicondylitis. 75 Patients referred to our clinic for treatment of lateral epicondilytis between January 1998 and December 2000 were randomly assigned to two groups based on their last Social Security number (SS#). Patients with odd ending SS# were assigned to the steroid group. Patients ending with even SS# were assigned to the autologous blood group. All patients were told that they would participate for a period of one year before surgery (failure)would be considered. Visits were spaced six weeks apart. After each visit a pain analog scale (0-10) was used to determine if further treatment was needed. Patients falling on the scale from 0-4 were treated conservatively. Patients falling on the scale from 5-10 were injected again. besides injections, stretching exercises, lifting with a supinated hand, pneumonic splint, ANSAIDS, were also enphasized or given. 39 pts. were treated with autologous blood. 36 patients were treated with steroid. 1 cc of Celestone mixed with 1cc 1 % Xylocaine and 1 cc 0.5% Marcaine was injected into the lateral epicondyle. 1 cc 0.5% Marcaine followed by 3cc autologous blood was injected into the lateral epicondyle in the second group. 10 pts with autologous blood and 12 with steroid injections were healed with one injection. 15 of the autologuos blood and 14 of the steroid goup responed to two injections. 9 patients in the autologous group and 12 in the steroid group responded to three injections. two patient in the autologous blood group and three in the steroid group failed and had surgery after one year. Autologous blood injection to the lateral epicondylar area seems to be as efficacious as steroid injection for the treatment of lateral epicondylitis.