In this randomized, double-blinded, parallel-group study, we compared the efficacy of tramadol and morphine administered IV for the management of pain in trauma patients in the prehospital situation. One-hundred-five patients were randomly allocated to receive tramadol (Group T) or morphine (Group M). The initial dose was 100 mg tramadol in Group T and 5 mg morphine (body weight < or = 70 kg) or 10 mg morphine (body weight >70 kg) in Group M; this could be increased to 200 mg in Group T and 15 or 20 mg in Group M if necessary. Pain intensity was assessed with four-point verbal rating scales. Sedation, physiologic data, and adverse events were also recorded. Analgesia was similar in both groups; the 95% confidence interval for the difference between the decrease in pain intensity observed with tramadol or morphine was -0.26 to 0.30, which was within the predefined equivalence range (-0.50 to 0.50). Neither sedation scores nor physiologic data differed between groups. Tramadol is an acceptable alternative to morphine in the prehospital trauma setting.