Introduction: Continuing professional development and education is vital to the provision of better health services and outcomes. The aim of this study is to contribute to the evidence base by performing a systematic review of qualitative data from studies reporting health professionals' experience of e-learning. No such previous review has been published. Method: A systematic review of qualitative data reporting UK health professionals' experiences of the ways in which on-line learning is delivered by higher education and other relevant institutions. Evidence synthesis was performed with the use of thematic analysis grounded in the data. Results: Literature searches identified 19 relevant studies. The subjects of the studies were nurses, midwives, and allied professions (8 studies), general practitioners and hospital doctors (6 studies), and a range of different health practitioners (5 studies). The majority of courses were stand-alone continuing professional development modules. Five key themes emerged from the data: peer communication, flexibility, support, knowledge validation, and course presentation and design. Discussion: The effectiveness of on-line learning is mediated by the learning experience. If they are to enhance health professionals' experience of e-learning, courses need to address presentation and course design; they must be flexible, offer mechanisms for both support and rapid assessment, and develop effective and efficient means of communication, especially among the students themselves. (Contains 1 table and 2 figures.)