Introduction: Self-assessment is a mechanism to evaluate one’s own performance and identify strengths and weaknesses. However, there is paucity of information on the the validity of self-assessment in the literature. This study is planned to assess the validity of medical students’ self-assessment skills in clinical examinations with long case during their postings in Obstetrics and Gynaecology. Methods: A cross sectional study was conducted during Obstetrics and Gynaecology (O&G) rotation assessing the students performance in the clinical long case examination. Participants were 80 fourth year medical students who were in their last week of their O&G rotation between August and December 2019. Each student was given a random case from the obstetric ward for the clinical long case examination during their final week of posting. At the end of examination, both student and examiner were tasked to independently evaluate the performance with a standardized grading sheet. Students were assessed in three areas namely Case Presentation (4 items), Case Discussion (4 items) and Professionalism and Overall approach to the practice of medicine (2 items). Results: The correlation coefficient was identified to be 0.307, p<0.01, indicating validity in self-assessment in the context of a clinical examination. The overall bias index was -0.97. Students underrated themselves in all areas with bias indexes of -0.35 in case presentation, -0.26 for case discussion and -0.35 in the professionalism and overall approach to practice. The correlation coefficients were 0.186, 0.360 and 0.170 respectively, indicating that in isolation only the component of case discussion showed significant correlation (p<0.01). Conclusion: Self-assessment in clinical examination is shown to be a valid assessment method when multiple assessment items are combined.