Present trends of community psychiatry are considered, with an assessment of their measurable parameters and degrees of feasibility. Three models are set forth, taking into account their principal factors: primary mental health agents, actual resources, socio political structures, geographical setting, cultural patterns, possible strategies, and community participation. Model I is a traditional one, and relies on decisions taken from the administration, which endows both scientific authority and normative power. Participation of the community is not called for, and has neither a place nor a function. The stress is on secondary and tertiary prevention. Model II is more focused on community needs and primary prevention. Programs are conceived after the community is consulted. They use primarily the health effectors within the community itself. Model III stresses active participation of community leaders and members at all levels of decision, and implementation, as well as the use of community's own resources for promoting health. Assistential centers and personnel are only the specialized supports and supervisors of actions, mainly carried out by the protagonists themselves. All three models are analyzed from several standpoints, including theoretical conception, feasibility of implementation, efficacity, vulnerability, cost benefit ratios and foreseeable outlooks.