In October 1994 a project was initiated by the General Practice Continuing Medical Education Tutors in the Department of General Practice at Sheffield University. The project sought to evaluate the efficiency (effort expended) and effectiveness (distance travelled) of a model of continuing professional development for general practitioners through individual portfolio‐based learning in co‐mentoring groups. Learning demonstrated through the portfolio was accredited for the postgraduate education allowance of participants. This paper addresses the process of portfolio development at the mid‐point of a year‐long trial to ascertain the strengths, weaknesses and possible future development of such a process within the context of continuing medical education.