The paper addresses issues in providing community services for people with both mental retardation and emotional or behavioral disorders. First, it explores the meaning often found at the root of the often elusive definition of dual diagnosis concluding that this has become a catch-all category for people who present existing service systems with the greatest challenges. Then it examines two, often conflicting, theoretical perspectives (the holistic versus the traditional behavioral perspective) underlying the widely varied approaches to services for these people. Finally, the crucial characteristics of integrated community-based services are discussed. These include small size, choice in roommates, functional programming, individualized planning, staff availability and flexibility, a long-term commitment, personalized service coordination, respect for autonomy and choices, individually tailored supports, flexible supports, and team support. Finally, the critical importance of forging enduring human relationships is stressed. (DB)