Objective: To examine the increase in self-perceived clinical competence during a three-year postgraduate training in general practice and to explore the relation between the growth of self-perceived competence and several background variables. Design: Cohort, 1995-1998. Setting: Three-year Postgraduate Training for General practice in the Netherlands. Participants: All Dutch trainees who followed postgraduate training from September 1995 to September 1998 (N=191). Intervention: We asked the trainees at the start and at the end of their postgraduate training to complete a questionnaire, which assessed their self-perceived knowledge, clinical skills and consultations skills. We collected information about potentially influencing background variables. Amongst these were variables such as: age, gender, prior medical experience, the effort someone has spent upon her/his education, insight in weak and strong areas of clinical competence and knowledge and skills levels. Main outcome measure: Self-perceived competence. Results: A total of 127 trainees completed both questionnaires (190 at the first administration and 128 at the second one). We found statistically significant growth of self-perceived clinical competence. Self-perceived consultation skills increased more than self-perceived knowledge and clinical skills. The afore mentioned background variables did not relate in any way with the growth of self-perceived clinical competence. Conclusion: This study shows that a 3-year postgraduate training in general practice enhances self-perceived clinical competence. However, we still do not know how to explain this improvement. Further study into the theoretical concept of self-assessment in medical education and into the factors contributing to the feeling of being competent, is required.