Introduction: Board certification has evolved from a "point-in-time" event to a process of periodic learning and reevaluation of medical competence through maintenance of certification (MOC). To better understand MOC participation, the transtheoretical model (TTM) was used to describe physicians' perceptions of MOC as a sequence of attitudinal changes. Method: Data were from a survey of internal medicine (IM) physicians' attitudes toward periodic reevaluation through MOC. An overall importance or decisional balance score was computed for each physician by summing his or her ratings across the 10 quality measures. The decisional balance score was used to classify physicians according to their acceptance of MOC, aligned with the 3 early TTM stages-of-change groups--precontemplation (PC), contemplation (C), and preparation (P)--where PC was least accepting and P was most accepting. Effect sizes assessed whether differences in attitudes toward reevaluation via MOC were of sufficient magnitude to support the TTM principles. Results: The difference in degree of acceptance of MOC between the P group and the PC and C groups was significant ("p" less than 0.001), but the effect size was lower than predicted by the "strong" principle. Resistance to MOC for the PC and C groups was significantly greater than the P group ("p" less than 0.001) and supported the "weak" principle. Physicians' beliefs about how often they should demonstrate performance on quality measures aligned well with the American Board of Internal Medicine's MOC requirements, with the P group believing in more frequent assessments than the PC and C groups ("p" less than 0.001). Conclusions: Results show that physicians in the Preparation stage had overcome resistance to MOC as predicted by the "weak" principle of the TTM, but their attitude scores about the benefits of MOC were below what was expected by theory. This suggests that the structure of MOC may have made it easier for physicians to overcome barriers to MOC participation but may have lacked adequate resources to promote the benefits of participating in the process. More effort is needed to understand the specific benefits of MOC for reevaluating competencies, how to engage physicians and other stakeholders in the design of MOC, and how to communicate the rationale and evidence to those who are less accepting of MOC. (Contains 3 tables.)