We retrospectively reviewed the results of arthroscopic adhesiolysis on postoperative knee stiffness in order to observe the clinical improvement and to evaluate the prognostic factors. Arthroscopic adhesiolysis without extraarticular procedure was performed in 31 knees displaying persistent flexion or extension loss. The causes of arthrofobrosis were previous ligament surgeries in 17 knees, surgery for a fracture involving the articular surface of the knee in 10 cases and other causes in four cases. The average range of motion was $60^{circ}(range,;14^{circ}-74^{circ})$ preoperatively, and improved by $120^{circ}(range,;7^{circ}-127^{circ})$ immediately following the procedure. The range of motion at the final follow-up (average 34 months) was $129^{circ}(range,;3^{circ}-132^{circ})$. In the 17 patients with arthrofibrosis fellowing ligament surgery, the range of motion was improved from $65^{circ}$ preoperatively to $135^{circ}$ at final follow-up. The improvement in function and motion was achieved during the first postoperative year. In the 10 patients with arthrofibosis following intraarticular fractures, the range of motion was improved from $60^{circ}$ preoperatively to $125^{circ}$ at the final follow-up, and most of the increase in motion was achieved within the first 6 months. Patients who suffered from a limitation of motion for less than 7 months gained an average $70^{circ}$ improvement in total range of motion following arthroscopic surgery. However, the total range of motion in patients with a duration of symptoms greater than 7 months improved by an average $49^{circ}$ postoperatively. In conclusion, arthroscopic adhesiolysis without incisional procedure is an effective therapeutic modality in arthrofibrosis of intraarticular origin. Improved outcomes can be expected in stiffness after ligament surgery and a symptom duration of arthrofibrosis less than 7 months.