Purpose: To evaluate the efficacy of the direct arthroscopic excision of a popliteal cyst without additional skin incision using a posteromedial portal based on minimum 2 year follow-up clinical results. Materials and Methods: From January 2003 to January 2010, 105 patients (111 cases) with popliteal cyst have been treated by a direct arthroscopic excision. Direct arthroscopic excision using a 70 degree arthroscopy and posteromedial portal can correct the valvular mechanism of capsular fold and reduce the complications with no additional skin incision at the popliteal area. In all cases, preoperative magnetic resonance imaging (MRI) was performed to detect combined intraarticular pathology. At 2 years postoperatively, a follow-up ultrasonography or MRI was performed to detect the recurrence of cysts. We used Rauschning and Lindgren criteria for clinical evaluation. Results: All cases had neither recurrence nor complaints of pain, swelling, or functional impairment more than 2 years after the surgery. At ultrasonography or MRI, no recurrence was found, and 5 complications were 1 skin lesion and 4 hematoma. Postoperatively, Rauschning and Lindgren criteria were more than grade 1. Conclusions: Direct arthroscopic excision using 70 degree arthroscope and posteromedial portal is an effective method for the treatment of popliteal cyst.