Objective: To compare the efficacy of combination therapy with ketorolac and morphine with monotherapy with each in patients with acute renal colic. Methods: This triple-blind, randomized clinical trial was conducted during a 6-month period from March to September 2014 in Northern Iran. We included 300 patients with clinical diagnosis of acute renal colic and pain score greater than 4 on 10 cm visual analogue scale (VAS) score. Patients were randomly assigned to three study groups to receive 0.1 mg/kg morphine in combination with 30 mg ketorolac (n=100), or only 0.1 mg/kg morphine (n=100) or only 30mg ketorolac (n=100). All the patients were evaluated at 0, 20 minute,40 minute later. Our outcomes were pain reduction and need for additive morphine in 20 and 40 minutes. We also recorded and compared the adverse effects between the study groups.Results: There was no significant difference between the study groups. The pain intensity was comparable between three study groups after 20-min of intervention. However, we found that the pain intensity was significantly lower in balanced analgesia group when compared to morphine (3.01±0.98 vs. 3.66±1.02; p=0.012) or ketorolac alone (3.01±0.98 vs. 3.68±0.88; p=0.018). However, those receiving the balanced analgesia, required significantly less rescue analgesia when compared to morphine (16% vs. 20%; p=0.041) or ketorolac (16% vs. 24%; p=0.012) alone. Conclusion: Balanced analgesia with morphine and ketorolac is more effective compared to morphine or ketorolac alone determine by lower pain scores after 40-min of injection and lower need for rescue analgesia.