Introduction: It was hypothesized that after a continuing medical education (CME) event, practice enablers and reinforcers addressing main clinical barriers to preventive care would be more effective in improving general practitioners' (GPs) adherence to cardiovascular guidelines than a CME event only. Methods: A cluster-randomized trial was conducted on a convenience sample of 122 GPs who were randomly assigned to either CME only (control group) or CME with practice enablers and reinforcers (PER group). In the PER group, nurses visited GPs' offices once a month to implement the clinical intervention on patients [greater than or equal to] 55 years old with a scheduled visit in the month following the nurse visit: (1) screening medical records for potentially undermanaged high-risk patients; (2) prompting physicians to reassess preventive care in these patients; (3) enclosing a checklist reporting most recent information relevant to guidelines' implementation; and (4) enclosing a summary of experts' recommendations in the form of a follow-up and treatment algorithm. Results: A retrospective chart audit of 2344 consenting patients, potentially undermanaged at baseline, demonstrated that the PER intervention following CME significantly improved adherence to guidelines compared to CME alone (OR: 1.78, 95% CI: 1.32-2.41). Discussion: The intervention was designed for self-implementation in primary care practices that have their own nursing staff. PER GPs were highly satisfied with the intervention; the majority said that they would implement it in their practice if someone trained their nurse, thus suggesting support for development of a multiprofessional CME program to disseminate this clinical approach to primary care practice groups. (Contains 6 tables and 2 figures.)