['Retrospective institutional database review.', 'To determine whether preoperative in-room time is a risk factor for surgical site infection (SSI).', 'Prior to spine surgery, while the patient is in the operating room, several procedures may be performed that may delay surgery. During this time, the sterile field may be exposed and may become contaminated. The hypothesis of this study was that the length of time in the operative room prior to surgical incision (anesthesia ready time [ART]) was related to the risk of SSI.', 'From 2005 to 2009, we identified 276 patients who developed SSI out of 7991 cases that underwent spine surgery from 2005 to 2009. Patient demographic factors, American Society of Anesthesiologists score, wound classification, number of levels, anatomic region, type of surgical approach, and length of surgery were extrapolated. ART was calculated as the time after the patient was brought into the operating room prior to surgical incision. Multivariate analysis was performed to identify risk factors for SSI.', 'Mean ART was significantly (P = 0.001) higher in patients with infection (68 min) compared with those without infection (60 min). The infection rate was higher in cases with ART more than 1 hour compared with those with less than 1 hour (4.9% vs. 2.3%, P = 0.001). In multivariate analysis, ART more than 1 hour was an independent risk factor for SSI, along with number of levels, American Society of Anesthesiologists score and posterior approach. The highest percentage of cases with ART more than 1 hour occurred in August and September.'] Does preoperative delay of more than 1 hour increase the risk of surgical site infection?