BACKGROUND Dexamethasone is frequently administered in the perioperative period to reduce postoperative nausea and vomiting. In contrast, the analgesic effects of dexamethasone are not well defined. The authors performed a meta-analysis to evaluate the dose-dependent analgesic effects of perioperative dexamethasone. METHODS We followed the PRISMA statement guidelines. A wide search was performed to identify randomized controlled trials that evaluated the effects of a single dose systemic dexamethasone on postoperative pain and opioid consumption. Meta-analysis was performed using a random-effect model. Effects of dexamethasone dose were evaluated by pooling studies into three dosage groups: low (less than 0.1 mg/kg), intermediate (0.11-0.2 mg/kg) and high (≥ 0.21 mg/kg). RESULTS Twenty-four randomized clinical trials with 2,751 subjects were included. The mean (95% CI) combined effects favored dexamethasone over placebo for pain at rest (≤ 4 h, -0.32 [0.47 to -0.18], 24 h, -0.49 [-0.67 to -0.31]) and with movement (≤ 4 h, -0.64 [-0.86 to -0.41], 24 h, -0.47 [-0.71 to -0.24]). Opioid consumption was decreased to a similar extent with moderate -0.82 (-1.30 to -0.42) and high -0.85 (-1.24 to -0.46) dexamethasone, but not decreased with low-dose dexamethasone -0.18 (-0.39-0.03). No increase in analgesic effectiveness or reduction in opioid use could be demonstrated between the high- and intermediate-dose dexamethasone. Preoperative administration of dexamethasone appears to produce a more consistent analgesic effect compared with intraoperative administration. CONCLUSIONS Dexamethasone at doses more than 0.1 mg/kg is an effective adjunct in multimodal strategies to reduce postoperative pain and opioid consumption after surgery. The preoperative administration of the drug produces less variation of effects on pain outcomes.