Public health agencies (PHA) and community mental health agencies (CMHA) generally are organizationally and functionally autonomous. Collaboration between PHA and CMHA was explored in a statewide survey of nursing directors of PHA (n = 135) and executive directors of CMHA (n = 214). Findings indicated staff did not know each other well; clients, funds, and information were infrequently exchanged; public health nurses rarely were included in planning for the care of those with mental illness; and satisfaction with relationships was minimal. Path analysis was used to test an interagency collaboration model. Awareness of staff from other agencies increased satisfaction with interagency processes and interagency relationships.