Although the model of a fully integrated system of co-located collaborative care is feasible only in fully integrated managed care systems, opportunities for improving collaboration between primary medical and mental health care providers often exist in other settings. The authors describe the efforts of a family medicine residency practice and a community mental health center to develop a co-located collaborative practice. A review of the collaborative practice after 18 months showed it to be modestly successful; changes have been implemented on the basis of feedback from providers and staff from both organizations. Communication between providers in the 2 systems has improved significantly, and additional collaborative services are planned for the near future. Despite multiple challenges involved, it is feasible for providers from 2 autonomous and highly bureaucratic systems to develop effective collaborative practice arrangements.