Findings are presented from a survey of administrators of county departments of mental health and alcohol and drug programs in California regarding services for individuals with co-occurring mental and substance abuse disorders. A total of 47 counties responded (84% response rate). The survey findings indicate that collaboration across county mental health and alcohol and drug services primarily occurs through information sharing, coordination of services, and joint projects. Fewer than one-half of the counties responding provide integrated programs, and the most frequently provided services are outpatient counseling and case management. Administrators cited historical differences between the two service systems and societal stigma as the greatest barriers to service delivery. Two opposing strategies for state action were suggested, either establishing specific funding set-asides or blending funding for services. Counties varied widely in their ability to estimate unmet service needs. Implications for policy development related to the dually diagnosed are discussed.