One hundred and nine patients undergoing upper limb surgery under an axillary plexus block were randomized to receive either intraoperative ketamine (n = 54) or placebo (n = 55; saline) for the prevention of severe rebound pain upon the cessation of a peripheral nerve block. All patients received an optimal preoperative multimodal analgesic treatment including intraoperative ketorolac and paracetamol. The primary outcome of this trial was to measure the incidence of rebound pain and the secondary outcome was to assess the risk factors associated with rebound pain in ambulatory patients. The results of this study illustrated that ketamine administration did not reduce rebound pain incidence or intensity. There were no differences in temporal summation and central sensitization inventory scores.