BACKGROUND. In 1969 the American Board of Family Practice (ABFP) became the 19th medical specialty board and the first since the inception of medical specialty certification to mandate recertification. As of July 1993, 16 other boards have adopted time-limited certification, but only two have reached the first recertification of their diplomates. As recertification approaches for the 14 boards, each will be faced with decisions concerning process, examination content and scope, and standards for passing. The physicians who will be facing mandatory recertification must be adequately prepared or accept the consequences of losing their certification. METHOD. This study examined the performances of six cohorts of family physicians–three cohorts of 711 practice-qualified physicians certified in 1971, 1972, and 1973, and three cohorts of 1,233 residency-trained physicians certified in 1977, 1978, and 1979–who were successfully recertified on successive six-year cycles from 1977 through 1991. Analyses of variance, multiple regression analysis, and Pearson correlation coefficients were used to investigate the relationships among the composite scores on the various certification and recertification examinations and among examination composite scores and demographic variables. RESULTS. There were significant (p < .01) declines in performance on each recertification examination. The residency-trained physicians had higher examination scores than did the practice-qualified physicians. Multiple regression analysis showed the last recertification score to be the strongest predictor of the next recertification score. The combination of previous scores and demographic variables resulted in the ability to predict between 63% and 74% of the variance in the most current recertification composite score. CONCLUSION. The results raise questions for further investigation, and such investigation may affect specialty boards' design of and/or examinees' test-taking strategies on future recertification examinations. For example, the decline in examination performance from certification through successive recertifications may result from factors related to the practice of medicine. It is possible that as the practice life of a family physician evolves, the focus of the practice becomes narrower, and this narrowed focus results in a decline in performance on an examination, half of which covers the breadth of the specialty. Thus, the medical specialties addressing mandatory recertification may wish to give thorough consideration to the focus of the examination–scope of specialty or scope of the practice, or some combination of both–as well as the implications of the standard-setting process used for recertification.