Objective. To develop and evaluate a modified OSCE assessing the assimilation and application of a range of ethical principles relevant to Obstetric and Gynecological practice. Setting. Candidates for an SpR training rotation Methods. Twenty six candidates working in Obstetrics and Gynecology were presented with four questions covering a range of relevant ethical scenarios. Their responses were assessed using a marking schedule. The marking schedule was evaluated against a checklist developed for assessing postgraduate medical examinations. Inter-rater reliability was assessed by calculating Kappa values for each question. The items in the marking schedule were also assessed to determine the level of agreement between the two examiners. To assess the contribution of each question to the total score, the question to total score correlations were calculated. The discriminatory capacity of each question was also assessed. Results. The development of the examination met almost all of the criteria in the checklist for developing a postgraduate examination. Inter-rater reliability was reasonable (4 weighted Kappas ranged from 0.53 - 0.75). There was a high level of agreement between examiners as to whether a candidate had answered an item on the marking schedule correctly. The degree of discrimination of items in the marking schedule was consistent with clinical opinion on the importance of questions. Conclusion. This modified OSCE examination demonstrates the feasibility of testing ethical principles relevant to practice in Obstetrics and Gynecology in candidates for postgraduate posts. It meets most of the criteria laid down in a checklist developed to assess postgraduate medical examinations