We report participant perceptions of the 2005-2006 C8 Health Project, a massive medical monitoring effort in response to perfluorooctanoic acid (C8) in West Virginia and Ohio. The C8 Health Project consisted of a health survey (n = 69,030), blood testing for ten per- and polyfluoroalkyl substances, and 50+ laboratory tests (n = 66,899). A randomly selected subgroup was surveyed in 2007 on (1) demographics (2) satisfaction with the project, and (3) perceptions of outcomes such as contribution to personal/family, community health, and links to health outcomes. The response rate was 573/1500 (38.2 percent). Most (92.7 percent) characterized their participation experience as "excellent" or "good," and most (96.2 percent) considered the project very "important," "important," or "moderately important." No demographic variable predicted important changes in satisfaction or perception of project importance. We conclude that responses to the survey indicate strong positive assessments of project benefits.