Policies affecting the type, amount, and organization of health and social services play an important role in the overall effectiveness of a service system. Countries differ markedly in their service systems, which vary in terms of the availability, accessibility, coordination, cost-effectiveness, and coerciveness of treatment and harm-reduction services. There are now a large number of evidence-informed health and social services that are ready for implementation in systems of care in both low and high-income countries. These interventions, along with innovations in the organization of service systems, can directly address access, equity, and coordination. Coordination between the criminal justice system, mental health services, primary health care, and the treatment system can reduce drug use, improve health, prevent crime, and decrease recidivism. Health and social services organized within an integrated system, can have an impact on the population in a variety of areas targeted by drug policy.