A framework for measuring psychological sense of community for community organizations was presented, and an instrument to measure community organization sense of community was developed. The framework consisted of four components: Relationship to the Organization, Organization as Mediator, Influence of the Community Organization, and Bond to the Community. Two studies examined the dimensionality, reliability, and validity of the instrument. Study 1 (n Ο 218) was conducted with participants from three community organizations, and it identified four factors, matching the framework, with alpha coefficients from .61 to .85. Study 2 (n Ο 1,676) was conducted with participants from five community organizations. Study 2 participants were 48% African American, 42% White, 6% Latino/Hispanic, and 3% Other. Also for the Study 2 sample, 69% were female; 31% were male. Study 2 confirmed three factors for the Community Organization Sense of Community scale (COSOC): Relationship to the Organization, Organization as Mediator, Bond to the Community; alpha coefficients ranged from .82 to .87. In three subsamples of Study 2, convergent validity of the instrument was explored by correlating total COSOC scores and subscale scores with two other measures of sense of community, political participation, community involvement, community organization involvement, and perceived safety. The patterns of correlation among the variables indicated, with one exception: strong support for