The discussion uses material presented at a 1991 conference on this topic sponsored by Rand's Drug Policy Research Center, as well as the experiences of some program demonstrations. The discussion focuses on the problems that make coordination between treatment and enforcement difficult. These include differences in perspective, differences in organizational incentives, ignorance, prejudice, different priorities, and practical problems. Although several possible methods exist for improving coordination among the law enforcement and treatment sectors, real cooperation will come about only when policy makers within the two sectors share common objectives and access to resources. 35 references and appended list of conference papers (Author abstract modified)