The objective of this systematic review was to evaluate the efficacy and tolerability of perioperative gabapentin administration for the control of acute postoperative pain. We searched Medline (1966-2006), the Cochrane Library (2006), Scopus, CINAHL and bibliographies from clinical trials and review articles. We included randomized controlled trials (RCTs) comparing gabapentin with inactive controls in surgical patients. Sixteen valid RCTs were included. Weighted mean difference (WMD) for postoperative pain intensity (0-100 mm visual analogue scale) was -16.55 mm at 6 h and -10.87 mm at 24 h for treatment with a single preoperative dose of gabapentin 1200 mg. Cumulative opioid consumption at 24 h was also significantly decreased with gabapentin (WMD, -27.90 mg). When gabapentin was administered at doses less than 1200 mg, pain intensity was also lower at 6 h (WMD, -22.43 mm) and 24 h (WMD, -13.18 mm). Cumulative 24 h opioid consumption was also lower (WMD, -7.25 mg). Gabapentin was associated with an increased risk of sedation (Peto OR 3.86; 95% CI 2.50-5.94) but less opioid-related side effects such as vomiting (Peto OR 0.58; 95% CI 0.39-0.86) and pruritus (Peto OR 0.27; 95% CI 0.10-0.74). In conclusion, gabapentin has an analgesic and opioid-sparing effect in acute postoperative pain management when used in conjunction with opioids.