Special patient populations can present unique opportunities and challenges to integrating primary care and behavioral health services. This article focuses on four special populations: children with special needs, persons with severe and persistent mental illness, refugees, and deaf people who communicate via sign language. The current state of primary care and behavioral health collaboration regarding each of these four populations is examined via Doherty, McDaniel, and Baird's (1996) five-level collaboration model. The section on children with special needs offers contrasting case studies that highlight the consequences of effective versus ineffective service integration. The challenges and potential benefits of service integration for the severely mentally ill are examined via description of PRICARe (Promoting Resources for Integrated Care and Recovery), a model program in Colorado. The discussion regarding a refugee population focuses on service integration needs and emerging collaborative models as well as ways in which refugee mental health research can be improved. The section on deaf individuals examines how sign language users are typically marginalized in health care settings and offers suggestions for improving the health care experiences and outcomes of deaf persons. A well-integrated model program for deaf persons in Austria is described. All four of these special populations will benefit from further integration of primary care and mental health services.