Objective. (1) To compare the rate of surgical site infections in ear surgery between groups with and without hair removal and (2) to study factors associated with surgical site infections. Study Design. A preliminary, randomized, controlled trial. Setting. University hospital. Subjects and Methods. The study was conducted in a group of 136 patients who underwent surgery for external or middle ear disease via the post-auricular approach at Chiang Mai University Hospital from May 2010 to May 2011. Demographic data, surgical site infection within 30 days postoperatively, and associated factors were recorded. Results. Fifty-eight cases were men and 78 cases women. Demographic data between the 2 groups were compared. Age, gender, the side of operated ear, types of anesthesia, emergency or elective setting, body mass index, history of alcohol and/or tobacco use, underlying diseases, operative time, and the length of hospital stay revealed no significant differences. A postoperative surgical site infection developed in 5 patients: 3 in the group with hair removal (4.5%) and 2 in the group without hair removal (2.8%) (P value = 0.674, Fisher's exact test). All infected cases had undergone mastoidectomy. Conclusions. Surgical site infection rates between the 2 groups (with and without hair removal) demonstrated no difference. Hair removal prior to ear surgery via post-auricular incision had no effect on the rate of surgical site infection. © American Academy of Otolaryngology - Head and Neck Surgery Foundation 2012.