We reviewed our results of nonoperative and operative treatment of chronic Achilles tenosynovitis to further define outcomes and treatment parameters. Forty-one patients presented with an average of 14 weeks of Achilles tendon symptoms. All patients received nonsurgical treatment initially, and 21 patients (51%) recovered after an average of 18 weeks of therapy. Three additional patients improved after brisement of the tendon/peritenon interspace. Seventeen of 41 patients eventually underwent soft tissue tenolysis and/or excision of degenerative tendon cysts. Those patients who responded to nonoperative therapy tended to be younger (average age, 33 years) than those who had degenerative tendon changes requiring surgery (average age, 48 years). All surgical patients were able to return to unrestricted activity after 31 weeks (range, 27-48 weeks). We believe 4 to 6 months of nonsurgical therapy is appropriate for middle aged patients or athletes with chronic Achilles tenosynovitis. Those that fail this treatment will improve with a limited debridement of diseased tissue without excessive soft tissue dissection of the tendon.