Abstract Background: Pain management results in better outcomes in traumatic patients in the emergency ward. Use of non-opioids facilitates the elimination of the adverse effects of opioid. Regarding this, the present study was conducted to examine the effect of ketamine as an adjunct to opioids for pain control in traumatic patients in a tertiary healthcare center in Tehran, Iran. Methods and materials: This double-blind randomized clinical trial was conducted on 160 traumatic patients admitted to the Emergency Department of Besat Hospital, Tehran, Iran, in 2018. The study population was randomly assigned into two groups of intervention and placebo. The intervention group one of which received 0.05 mg/kg opioid (i.e., morphine) plus 0.1 mg/kg ketamine, and placebo group the other one was provided with the same amount of morphine opioid plus placebo. The pain was recorded up to 120 min and compared between the groups. Results: Based on the obtained results, 23 (28.8%) and 16 (20%) patients in the ketamine intervention and control placebo groups had side effects, respectively, showing no significant difference (P=0.197). In addition, the pain significantly reduced in both groups (P=0.001). However, the results of repeated measures ANOVA revealed no statistically significant difference between the two groups in terms of pain reduction trend (P=0.275). Conclusion: Based on the results, it can be concluded that ketamine has no superior effect when administered as an adjunct to opioid for pain control in traumatic patients.