摘要:Purpose: The knowledge loss or longevity of taught lessons is a major concern in medical students and all medical practitioners. This study evaluated the physiology knowledge loss in medical students in Ahvaz Jundishapur University of Medical Sciences in Iran. Methods: A total of 265 volunteers from medical students who had previously passed the “general exam of medical basic sciences” at the end of fifth semester took a retention test (RT) to evaluate their knowledge loss of physiology. The candidates were divided into ten groups depending on the semester (S) they were passing at the time of study: 41 students in preclinical levels (S6 and S7), 123 students in externship levels (S8, S9, S10, S11 and S12), and 101 students in internship levels (S13, S14 and S15). The RT consisted of 20 multiple choice questions from all topics of medical physiology, including central nervous system, endocrine, gastrointestinal, cardiovascular, respiratory, renal, blood, and cellular. Results: Findings showed that there was a decreasing trend of knowledge loss from S6 to S15. The lowest level of knowledge loss was observed in S15 students. These results also demonstrated that knowledge loss in male medical students was more than that in female students. Conclusion: These findings indicated that the physiology knowledge loss trend is inversely correlated with the time passing. We conclude that the reason is that physiology is a basic science which is most applicable during medical students’ clinical years.