Background Hip arthroscopy is performed with increasing frequency in the treatment of femoroacetabular impingement. This technique has a significant learning curve and requires special training. This study aimed to determine how preoperative and intraoperative factors and surgeon experience affect the incidence of complications. Methods A prospective multicenter cohort study was conducted, which included 362 procedures in 360 patients undergoing hip arthroscopy for treatment of femoroacetabular impingement, with a minimum follow-up period of 6 mo. Complications were classified as minor if the patient's health or physical performance was not compromised, and as major if a patient's health or physical performance was affected or if reoperation was required. The group was divided in two chronologically: the learning curve group composed of the first 50 surgeries of each surgeon for a total of 150 hips in this group and the post-learning curve group, composed of the remaining 212 hips. Results Minor complications occured in 24.3% (88/362) and major complications in 1.1% (4/362). A positive association between the incidence of complications and learning curve (P<0.001) was found. Forty-four percent of the patients in group 1 had complications whereas only 12.7% in group 2. A positive association between traction time and minor complications was found. A traction time longer than 90 minutes increased the probability of sensitive neurological injury by a factor of 2.9 (RR 2.913; CI 95%; 1.875 - 4.526; P<0.001). Conclusions Hip arthroscopy is technically demanding and requires a learning curve to improve results. In our experience, the most frequently reported complication was transient neurological injury caused by prolonged traction times.