Background: Postgraduate medical e-learning (PGMeL) is being progressively used and evaluated. Its impact continues to grow, yet there are barriers to its implementation. Although more attention is now being paid to quality evaluation models, little has been written about the successful implementation of PGMeL. This study aims to determine factors and define themes influencing the successful implementation of PGMeL. Methods: We performed 10 semi-structured interviews with experienced e-learning creators, after which we carried out a thematic analysis to name and describe factors and themes. Results: Although this was not the objective of the study, the participants stressed the importance of a definition of success. Associated with this definition were: reaching your target audience, achieving learning aims, satisfying your audience and maintaining continuity. Three themes were identified containing eleven factors that influence successful implementation. The themes were named and defined after the group that had the most influence on the factors. We named them creator-, organization- and learner-dependent factors. The creator dependent factors are: the learning aim, pedagogical strategies, content expertise, evaluation and the creators motivational path. The organization dependent factors are management support, recourse and culture. Finally, the learner dependent factors are technology, motivators/barriers and value. Conclusions: This study shows that implementing PGMeL has creator-, organization- and learner-dependent factors which should be taken into account during the creating of the PGMeL. Although creator- and learner-dependent factors are mentioned in other studies, the present study also stresses the importance of organization-dependent factors. Innovation implementation theories such as Rogers' diffusion of innovation or Kotter's eight steps of change management show a great overlap with these factors. Future studies can both evaluate the use of these innovation models in creating PGMeL and assess the effect of the organizational factors in greater depth.