A consortium of researchers from the South African Medical Research Council, Human Sciences Research Council, University of Cape Town and Dopstop was established to identify, summarise and integrate findings from substance abuse research conducted in the province over the last eight years. A review of research conducted since 2000 was done and compiled into a summary report of key findings on substance abuse trends in the Western Cape. The report provides recommendations for interventions and outlines gaps in current knowledge that will assist the Department of Social Development in identifying research needs and service planning. This report reveals that alcohol remains a significant substance of abuse in the Western Cape. Alcohol abuse is often not a key focal point for prevention and treatment services and yet places a tremendous burden on the health and social welfare sectors in both urban and rural areas of the province. Effective interventions that address alcohol use among all race and gender groups are hence required. This report also highlights the growing use of stimulants in the province (such as methamphetamine and cocaine). Stimulant abuse is associated with a myriad of problems, especially sexual risk behaviour. Effective interventions for treating stimulant-related problems are urgently required in the province. Stimulants are also not used in isolation. This report highlights the use of other classes of drugs, such as opiates, cannabis and sedatives to come down from a stimulant-induced high. These drugs pose their own set of health and social problems. In summary, these findings show that no single substance should be viewed in isolation. Substance abuse services should therefore focus on preventing and treating poly-substance use. This report identifies several gaps in current knowledge on substance use in the province. Given the scale of the substance abuse problem in the Western Cape, funding for research on substance use has been limited. A comprehensive research strategy that includes a province-wide, dedicated household survey focused on substance abuse; continued support for the SACENDU and district social services surveillance systems; regular school-based surveys; and ongoing intervention research is required. Together, this research will provide the DOSD with up to date information on the prevalence of substance use disorders in the province, changing patterns of substance use, geographical areas where treatment and prevention needs are greatest, and data on substance use in remote and rural areas of the province. To ensure that this strategy is successfully implemented, adequate funding should be ear-marked for these initiatives. This report also emphasises the need for intervention research to develop effective means of preventing and treating the harms associated with substance use, particularly substance-related injuries and substance related sexual risks. This intervention research should also focus on establishing the cost-effectiveness, efficiency and effectiveness of current prevention and treatment services in the province. Intervention services are also needed to address substance abuse among vulnerable populations, such as rural and Black/African communities and among women.