CHCs and AHACs have an explicit mandate to comprehensively serve the health needs of population groups with barriers to access to care including disadvantaged groups in urban settings and geographically dispersed populations in northern, rural and underserviced areas. The question the study sought to answer was: “If we identify the distribution of the 2-3 million people who most need CHC or AHAC services (according to population needs-based models), how could resources to support an additional 250,000 Ontarians be distributed so that the Priority Populations could have equitable access to community-based primary health care wherever they live Ontario?” The results would need to support Five Strategies (Aboriginal, Francophone, Urban, Southernrural and Northern-remote) and ideally achieve equity among them and across Ontario. We created a priority population that included many of the groups that are identified priority populations of CHCs and AHACs. These include: low income people, Aboriginal Peoples, Francophones, people with a disability or activity limitation due to a long term physical or mental health problem, recent Immigrants and non-permanent residents (e.g. refugees, migrant workers), racialized groups, and people living in areas with geographic access barriers. The population groups are the main groups other than age and sex for which detailed data is available that can be used to estimate the number of people with multiple potential barriers to access. The study used multi-way cross tabs of the 2006 census (purchased for the 141 secondary subLHIN geographies) supplemented by: rurality scores at the census subdivision level that were rolled up into subLHINs; updated poverty rates (after-tax LIMs, 2008); and updated Aboriginal data (Indian Register, 2009). All the data was standardized up to the 2009 population estimates obtained from MOHLTC for the 141 subLHIN community planning areas. A priority population was produced that was a subset of the above groups that totalled 2.7 million excluding all the overlaps. This included all low income people, all Aboriginal peoples (to the extent possible given data limitations), Francophones with multiple potential access barriers, and people living in high RIO areas with multiple potential access barriers. Additional larger priority populations were also created but not used in the results prepared in this study. Minimum service equity targets were set (ranging from 25% to 50%) for each population group and geographic area type (six geographic area types were created). Targets were set higher for Aboriginal peoples and in remote areas. The number of people being served by CHCs and AHACs was tabulated by geocoding client records with postal codes to the 141 subLHINs and distributing clients without postal codes according to a set of guidelines and the individual expansion status of each CHC or AHAC. Subtracting existing clients from the service equity targets results in calculated service gaps for each population and subLHIN. These results provide one input to a priority setting process that would also consider the accessibility of services provided by other primary health care models and community preferences, etc.