We investigated the anesthetic and analgesic effectiveness of adding dexamethasone to lidocaine for IV regional anesthesia (IVRA). Seventy-five patients undergoing ambulatory hand surgery were randomly assigned to one of three groups: group L received 3 mg/kg lidocaine, group LD received 3 mg/kg lidocaine + 8 mg dexamethasone, and group LDc received 3 mg/kg lidocaine for IVRA and 8 mg dexamethasone IV to the nonsurgical arm. IVRA was established using 40 mL of a solution. Visual analog scale and verbal pain scores were recorded intraoperatively and for 2 h post-operatively. Postoperative pain was treated with oral acetaminophen 500 mg every 4 h when visual analog scale score was more than 3. Time to request for the first analgesic and the total dose in the first 24 h were noted. Times to onset of complete sensory and motor block were similar in the 3 groups. The times to recovery of motor block (L = 8 [5.91-10.08] min, LD = 13 [6.7620.19] min, LDc = 6 [4.44 - 8.43] min) and sensory block (L = 7 [5.21-10.30] min, LD = 12 [6.11-19.40] min and LDc = 6 [4.2-8.11] min) were longer in group LD (P < 0.05). Patients in group LD reported significantly lower pain scores and required less acetaminophen in the first 24 h after surgery. In conclusion, the addition of 8 mg dexamethasone to lidocaine for IVRA in patients undergoing hand surgery improves postoperative analgesia during the first postoperative day.