BackgroundThis paper presents the findings of a rapid needs assessment conducted at the request of the local health authority responsible for health care services, the Toronto Central Local Health Integration Network (Ontario, Canada), to inform health and social service planning.MethodsWe utilized concept mapping methodology to facilitate engagement with diverse stakeholders–more than 300 community members and service providers–with a focus on hard to reach populations. Key informant interviews with service providers were used to augment findings.ResultsParticipants identified 48 unique services or service approaches they believed would improve the health of residents in the area, including those addressing health care, mental health and addictions, youth, families, people experiencing homelessness, seniors, general social services, and services targeting specific populations. While service providers consistently identified a critical need for mental health and addiction services, community members placed greater importance on the social determinants of health including access to housing, job placement supports and training and service accessibility. Both groups agreed that services and programs for seniors and people experiencing homelessness would be highly important.ConclusionOur study provides a unique example of using concept mapping as a tool to aid a rapid service gap analysis and community engagement in a metropolitan area. The findings also reinforce the importance of working cross-sectorally, using a Health in All Policies approach when planning services for underserved populations.