From August 1989 to January 1995 we performed multiple percutaneous longitudinal tenotomies under local anesthetic on 52 middle- and long-distance runners with unilateral Achilles tendinitis or peritendinitis that had failed conservative treatment. Forty-eight patients were reviewed at an average of 22.1 months (SD, 6.5) after surgery. Results were rated as excellent in 25 patients, good in 12, fair in 7, and poor in 4. Four patients developed subcutaneous hematomas. One patient developed a superficial infection at one of the incision sites, which was managed by oral antibiotics with full recovery. Three patients complained of over-sensitivity to the incisions; this was resolved by rubbing hand cream over the incisions several times a day. One patient developed hypertrophic painful scars on three of the five incisions, but corticosteroid injections yielded good functional and cosmetic results. Isometric strength and endurance of the gastrocsoleus complex was measured just before the procedure, and at 6 weeks and 6 months later. Both were within 10% of the normal contralateral limb by the 6th postoperative month. Percutaneous longitudinal tenotomy is simple, can be performed on an outpatient basis, requires minimal follow-up care, and, in our experience, has produced no significant complications. We use this procedure as the operative treatment of choice for cases of chronic tendinitis that have failed conservative treatment.