Evidence-based crime prevention ensures that the best available evidence is considered in the decision to implement a program designed to prevent crime. Through the use of the highest quality scientific evidence and the most rigorous and transparent review methods, successful assessments of what works have occurred. The state of science on what works to prevent crime is presented in four areas: family-based prevention (i.e., home visitation, parent training, multisystemic therapy), community-based prevention (i.e., gang member intervention programs focusing on reducing cohesion, community-based mentoring, after-school recreation, school-based prevention (i.e., school and discipline management, self-control or social competency instruction using cognitive-behavioral instruction methods), and placed-focused prevention (i.e., nuisance abatement, closed circuit television surveillance, improved street lighting). Developments in the international arena of evidence-based crime prevention include: Campbell Collaboration Crime and Justice Group, Crime Reduction Program (CRP) in England and Wales, and innovative efforts in Australia. The implications for Canada indicate that the Canadian system of new crime prevention programs incorporating high quality evaluation designs is needed in order to create a foundation for evidence-based crime prevention now and in the future. Funding decisions need to be guided by evidence on what works best. The Canadian research program needs to be initiated to understand how scientific evidence on what works best can be incorporated into crime prevention policy and practice. References