Oral viva examinations remain integral to medical education, though concerns about inconsistency and examiner bias persist. The traditional viva (TV) permits deeper inquiry but often compromises fairness and standardization. The structured viva (SV), with predetermined questions and marking schemes, aims to enhance objectivity and syllabus coverage. This study compared these two formats in undergraduate physiology, assessing student performance, perceptions, and examiner feedback. This observational study was conducted among 100 first-year MBBS students, each undergoing both TV and SV. The SV comprised four stations - case scenario, instrument, graph, and laboratory report - each three minutes and five marks, assessed by four examiners. Viva scores were compared, and correlations with theory, practical, and combined marks were analyzed. Questionnaires captured perceptions regarding stress, fairness, and coverage from both students and examiners. There was no significant difference in mean scores between TV and SV. However, SV scores correlated more strongly with theory and combined theory–practical marks, while correlations with practical marks were similar across both formats. The majority of students preferred SV, citing greater fairness, transparency, and reduced anxiety, though some valued the flexibility of TV. Examiners highlighted SV’s strengths in standardization and coverage but noted increased preparation demands and reduced opportunity for probing. In summary, while TV and SV produced comparable scores, SV demonstrated stronger validity by aligning more closely with overall performance. Incorporating SV, with measures to enhance its flexibility, may help optimize viva examinations by balancing reliability with educational value.