A retrospective analysis of 68 knees from 65 patients older than 40 years, who had undergone a partial medial meniscectomy, was carried out. The average age of the patients was 49.7 years (range, 40 to 74), and the mean follow-up period was 7.8 years (range, 5 to 11). The patients were divided into two groups based on the degree of articular cartilage degeneration. Group I consisted of 53 knees that did not have any significant articular cartilage damage beyond grade I or II. Group II consisted of 15 knees that had grade III or IV cartilage damage. Overall, excellent results were obtained in 44 patients (47 knees), good results in 10 patients, fair results in six patients, and poor results in five patients. In group I, 46 knees (87%) had an excellent outcome, and only one patient had a poor result. In contrast, patients in group II had significantly worse results, with only one knee (7%) having excellent outcome, and four knees had a poor result. A specific history of trauma did not affect the clinical outcome. Forty-two patients (64%) were able to resume normal athletic activities without any restrictions. Arthroscopic partial medial meniscectomy in patients older than 40 years is an acceptable and effective long-term treatment, particularly in patients without significant articular cartilage damage.