Objective: To explore the perceptions of General Medical Practitioners and pharmacist supplementary prescribers of the training provided for qualification as a pharmacist supplementary prescriber, and the experience of pharmacist supplementary prescribers of subsequent continuing professional development in practice. Design: A qualitative study of pharmacists from the first wave of those trained to become pharmacist supplementary prescribers, comprising interviews, focus groups and documentary analysis of recorded critical incidents. Setting: The research was conducted in three general practices located in two primary care trusts in the UK Midlands. Each practice had a pharmacist supplementary prescriber. Eight pharmacist supplementary prescribers participated, seven of whom were prescribing, all in a general practice setting. Method: A practice-specific focus group was held in each of the three general practices. Two focus groups were held for pharmacists and seven pharmacists were interviewed, six of whom provided two or more critical incidents. Results: Pharmacists were critical of some aspects of the academic training but were unanimous in acknowledging the value of the period of learning in practice and the input of their Designated Medical Practitioner. Learning was recognized by both parties as being reciprocal. Pharmacists' accounts illustrated a variety of ways in which they undertook continuing professional development, with learning on the job a key component. There was little consensus between General Practitioner partners in two of the practices on the appropriateness of pharmacist supplementary prescribing, discussion focusing on the acquisition of clinical skills. Some partners, particularly those who were Designated Medical Practitioners, saw potential benefits. Conclusion: The coaching relationship between General Practitioner Designated Medical Practitioners and pharmacists served to embed skills and enhance confidence.The reflection skills gained by the pharmacist supplementary prescribers during their academic learning period appear to be important in their subsequent work-based learning.