Objective: To determine the anatomy knowledge in postgraduate obstetrics and gynaecology trainees. Our hypothesis was that trainees possess a good knowledge of anatomy and, on average, would correctly answer at least 80% of questions on core anatomy knowledge. Design: A 10-year longitudinal study. Setting: This study included the results from annual progress tests over 10 years (2010–2019) that were completed by Dutch obstetrics and gynaecology postgraduates. Population: Dutch trainees in the field of obstetrics and gynaecology. Methods: Anatomy questions included in a yearly progress test were assessed for their relevance. Relevance was determined according to a previous Delphi study, which identified 86 structures that are essential for the safe and competent practice of general gynaecologists. Scores on relevant anatomy questions were calculated. Main Outcome Measures: The mean percentage correct answers. Results: Of all 1637 questions of the yearly progress test, 54 were anatomy-related questions (3.3%). Of these 54 questions, 38 (70%) were considered as relevant questions. The mean 10-year correct response rate on relevant questions was 64.5%. Conclusions: The anatomy knowledge of obstetrics and gynaecology trainees is insufficient. Our results highlight the need to test and improve anatomy knowledge during postgraduate obstetrics and gynaecology training. Funding: None. Keywords: anatomy knowledge, progress testing, obstetrics and gynaecology, postgraduate training