Adolescent mental health workers are generally poor at identifying and treating co-existing alcohol and other drug (AOD) disorder. This study aimed to evaluate the utility and acceptability of an AOD screening and brief intervention (BI) training package delivered to child and adolescent mental health workers and its impact on relevant attitudes, skills and knowledge. Quantitative data was collected before and after the BI training using a 55-item questionnaire. Focus groups explored issues around AOD screening and BI implementation in practice. The questionnaire and focus group were repeated 10 months later to ascertain change in behaviour. The BI training was well-received and led to improvements in attitudes, skills and knowledge around AOD screening and BI in youth mental health practitioners. Positive change in participants' attitudes to performing screening and BI were demonstrated. Low response rates at follow-up limited analysis of behaviour change.