OBJECTIVES: This paper describes current and potential roles of public health nurses in the care of adults with serious mental disabilities and explores incentives and barriers to the expansion of the role of public health nurses in this area. METHODS: One hundred thirty-five directors of nursing of public health agencies and 214 executive directors of mental health agencies in Ohio responded to a survey about public health nurses' roles and incentives for and barriers against increasing their role in mental health care. RESULTS: The majority of respondents reported that public health nurses work with adults with serious mental disabilities but perceived their role with these clients to consist primarily of making referrals and providing physical health care. Both groups of directors saw the potential for increasing the nurses' roles in these same areas and reported that the major barrier to expanding their roles was lack of financial support. Directors of nursing expressed interest in expanding these roles if they received additional financial support and the nurses received education and consultation. Executive directors were willing to provide the education and consultation but generally were not willing to provide financial support. CONCLUSIONS: Better utilization of public health nurses in the care of adults with serious mental disabilities could improve client health care and make more efficient use of scarce health care resources.