People with schizophrenia, who have disturbances in mood, thought processes and behavior, experience impairment in day-to-day functioning. Primary caregivers have tried to become involved in caring for persons with schizophrenia by coordination with community psychiatric nurses. Community psychiatric nurses have an important role to play in supporting families in this care, especially primary caregivers. The purpose of the present study was to explore the relationship between Thai community psychiatric nurses and primary caregivers of people with schizophrenia. Grounded theory methodology was used to examine the process with which community psychiatric nurses work together with primary caregivers. Purposive sampling and theoretical sampling were used. Data were collected from 34 informants, including 17 community psychiatric nurses and 17 primary caregivers through in-depth interviews, observation, and field notes. Data was analyzed using constant and comparative methods by Glaser (1978). The study revealed that building collaboration in the care of people with schizophrenia involved coordinating both community psychiatric nurses and primary caregivers in a process that consists of five major stages. In the first stage, community psychiatric nurses and primary caregivers used strategies to establish trust in each other before the next stage, which engaged their concerns and needs. Later, the stages of mutual preparation for caregiving, cooperating on patient care and monitoring outcomes were jointly employed in order to promote a healthy family life for patients. The study concludes by suggesting guidelines and giving insights into ways of helping primary caregivers and their patients with schizophrenia.