High-quality colposcopy is essential in cervical cancer prevention. We performed a multicentre prospective interventional pilot-study, evaluating the effect of a six-hour case-based colposcopy course on short- and long-term learning of colposcopy-related knowledge, diagnostic accuracy levels and confidence. We recruited 213 colposcopists participating in three European Federation of Colposcopy (EFC) basic colposcopy courses (Finland, Norway, UK). The study consisted of three tests with identical content performed before, after and 2 months after the course, including ten colposcopic images, ten patient cases and scales for marking confidence in the answers. Outcome measures where mean scores in correct case-management, diagnosis (including high-grade lesion recognition), transformation-zone recognition and confidence in answers. Results were compared between the three tests and stratified according to experience. Mean test scores improved after the course for all participants. The increase was highest for beginners. Confidence in answers improved and the number of colposcopists showing high confidence with low scores decreased. A structured case-based course improves skills and confidence especially for inexperienced colposcopists; however, trainers should be aware of the risk of overconfidence. To complement theoretical training, further hands-on training including high-quality feedback is recommended. Conclusions drawn from long-term learning are limited due to the low participation in the follow-up test.