Our objective was to explore the effectiveness of community action as a strategy for health promotion, through a critical review of five years of community action evaluation literature.Community action was defined as a health promotion, program that involved the community in implementation and control of the process of the program. Criteria for scientific evaluation of programs were proposed for sampling and control procedures, reliability and validity of instruments, analysis techniques, and specification of details of the intervention. A critical review of the literature, located by an on-line and related reference search, was undertaken for community action aimed at reducing cancer and cardiovascular disease, between January 1990 and May 1995.None of seven community action studies (17 articles) that examined cancer risk factors fulfilled all the criteria for rigorous scientific evaluation. The most methodologically adequate cancer study, the COMMIT intervention, had only a moderate degree of success in reducing community smoking rates. Similarly, none of the six studies (25 articles) on cardiovascular disease fulfilled all the criteria. The results for the most methodologically adequate study, the Minnesota Heart Health Program, were disappointing, with strong secular trends preventing adequate assessment of the intervention effect.The finding that none of the reviewed studies met all evaluation criteria was due to several factors, including political considerations, feasibility, and the continued evolution of the science of evaluation in health promotion. Some important questions are posed for researchers by the failure of methodologically superior projects, such as COMMIT, to show major gains in reducing health risk behaviors.