Objective: This study sought to (1) provide estimates of alcohol and illicit drug use, alone and in combination, among a sample of adult emergency department patients and (2) examine readiness to change. Methods: Consecutive emergency department patients >= 18 years of age from a large regional hospital in Camden, NJ, were enrolled from May to December 2005. Patients provided information on alcohol and illicit drug use, as well as on interest in quitting each of these substance classes. Results: Of the 1549 subjects surveyed, 98 (6%) indicated weekly use of both alcohol and illicit drugs, and 58 (4%) indicated problems associated with use of both substance classes. Problem users of illicit drugs felt that quitting drugs was more important, that they were more ready and that they were more confident in quitting than problem users of alcohol. Conclusion: Problem use of multiple substances was relatively common in this emergency department sample. A substantial proportion of problem users of both substance classes were highly motivated to quit the use of one, but not the other, substance class. Further longitudinal and clinical trial research is needed to study the implications of multiple substance use, motivation to change and cessation.