The mental health screening instrument revealed high rates of co-occurring mental health symptoms. Almost 40 percent (n=18) of the youth screened had a depressive syndrome, and 23.4 percent (n=11) had an anxiety syndrome. Just over 42 percent (n=20) had a positive psychosis screen, and 319 percent (n=15) met criteria for a manic syndrome. The instrument had a high level of internal consistency in its shortest format and required approximately 13 minutes to administer. The longer format took 30 minutes to administer. Although AOD workers complained about the length of time required to administer the screening instrument, the youth who were screened reported that the time required was acceptable, felt comfortable completing the instrument, and found the items relatively easy to understand. Still, the length of the instrument should be shortened and the content simplified. The study was conducted at two public youth AOD services in Melbourne, Victoria. Participants consisted of all AOD workers in the outreach teams of both services (n=30). Twenty (80 percent) of the workers were followed-up at 12 months after training in the use of the screening instrument. AOD workers received four half-day training sessions on mental health screening. The training included a rationale for incorporating mental health screening into practice, an overview of mental health and co-occurring disorders, as well as training in the administration and interpretation of the mental health screening tool, suicide risk assessment, and management. Eighty-four youth completed the screening tool. 4 tables and 34 references