BACKGROUND: To evaluate the educational effects of a clinically integrated e-learning course for teaching basic evidence-based medicine (EBM) among postgraduates compared to a traditional lecture-based course of equivalent content. METHODS: We conducted a cluster randomised controlled trial in the Netherlands and the UK involving postgraduate trainees in six obstetrics and gynaecology departments. Outcomes (knowledge gain and change in attitude towards EBM) were compared between the clinically integrated e-learning course (intervention) and the traditional lecture based course (control). We measured change from pre- to post-intervention scores using a validated questionnaire assessing knowledge (primary outcome) and attitudes (secondary outcome). RESULTS: There were six clusters involving teaching of 61 postgraduate trainees (28 in the intervention and 33 in the control group). The intervention group achieved slightly higher scores for knowledge gain compared to the control, but these results were not statistically significant (difference in knowledge gain: 3.5 points, 95% CI -2.7 to 9.8, p = 0.27). The attitudinal changes were similar for both groups. CONCLUSION: A clinically integrated e-learning course was at least as effective as a traditional lecture based course and was well accepted. Being less costly than traditional teaching and allowing for more independent learning through materials that can be easily updated, there is a place for incorporating e-learning into postgraduate EBM curricula that offer on-the-job training for just-in-time learning. TRIAL REGISTRATION: TRIAL REGISTRATION NUMBER: ACTRN12609000022268. ; Regina Kulier, Sjors FPJ Coppus, Javier Zamora, Julie Hadley, Sadia Malick, Kausik Das, Susanne Weinbrenner, Berrit Meyerrose, Tamas Decsi, Andrea R Horvath, Eva Nagy, Jose I Emparanza, Theodoros N Arvanitis, Amanda Burls, Juan B Cabello, Marcin Kaczor, Gianni Zanrei, Karen Pierer, Katarzyna Stawiarz, Regina Kunz, Ben WJ Mol, and Khalid S Khan