Despite considerable effort directed towards youth focused prevention activities in South Africa, little is known about the content of these activities. A major concern is the extent to which substance abuse prevention programmes reflect evidence-based practices (EBPs). This paper reports on the findings from a cross-sectional audit of youth-focused alcohol and other drug prevention programmes conducted in the Cape Town Metropole in 2007. This audit explored the extent to which EBPs are used in prevention programmes and examined possible barriers to their adoption. Key findings suggest that most prevention programmes are not guided by EBP and are implemented in the absence of evidence on their effectiveness. The lack of a national regulatory regime for prevention programmes and limited funding are major barriers to implementing sustainable and effective prevention programmes. Based on these findings, strategies to assist in improving substance abuse prevention services and recommendations for improving service delivery systems are provided.