It is not unusual that narcotics-dependent patients fulfill their medical requirements in the emergency department (ED). The behavior of these patients varies, and their manifestations and predictors are still not fully studied. We performed this retrospective study by prospectively collecting data on patients with suspected drug dependence who were undiagnosed at first and then treated for some kind of reported pain at the ED. Patients who were confirmed to have narcotics dependence were compared with control patients in a ratio of 1:3 matching for age, gender, disease, and clinical diagnoses. From January 2006 to October 2009, 26 of 223 patients treated for pain were found to be drug dependent (12 males and 14 females). The average dose of narcotics used was higher than the control group [3.23 ± 1.14 vs. 1.12 ± 0.36, p