Background Several studies have reported functional recovery of the shoulder after arthroscopic rotator cuff repair (ARCR). Preoperative estimation of the time required for functional recovery is important for determining surgical indications and for planning timing of the surgery and an appropriate postoperative physical therapy. Questions/purposes We therefore asked: (1) how long it takes to obtain functional recovery after ARCR, and (2) what preoperative factors influence functional recovery time. Patients and Methods We retrospectively evaluated 201 patients who had undergone ARCR. Using the Japanese Orthopaedic Association (JOA) shoulder scoring system, we defined the functional recovery period as the time required to achieve a score greater than 80% in each component. We evaluated the functional recovery periods and assessed preoperative influencing factors such as age, gender, shoulder stiffness, morphologic features of rotator cuff tears, and rotator cuff tear size. Results Sixty-three patients (31%) took less than 3 months, 81 patients (40%) took between 3 and 6 months, and 57 patients (28%) took greater than 6 months to achieve a score greater than 80% in each JOA shoulder assessment component. Younger patients without shoulder stiffness and with smaller rotator cuff tears had shorter functional recovery periods. Conclusions One hundred forty-four patients (72%) obtained functional recovery within 6 months after ARCR. Age, shoulder stiffness, and rotator cuff tear size influenced functional recovery time.