One of the problems that both medical students and educational programmers are involved in is the importance of basic science materials in comprehension of clinical subjects and students performance after that. Our goal is to measure the correlation coefficient between the CBSE and CPSE and the predictive validity of CBSE for CPIE. Analytic cross-sectional study was conducted on 103 (52 males and 51 females) of Rafsanjan medical students of different years. Independent T-test was used for comparison of means of CBSE and CPIE in both sexes. The relationship between CBSE and CPIE scores and predictive validity of CPSE for CPIE was assessed by Pearson correlation coefficient and simple linear regression analysis. Mean of CBSE was 122.71±16.71 in males and 119.70±14.82 in females. Mean of CPIE was 118.73±13.45 in males and 118.21±16.81 in females. There wasn't any significant difference between two sexes for these two scores. The correlation coefficient was 0.593 in all students and predictive validity was 0.358. These values were 0.513 and 0.263 in males and 0.696 and 0.485 in females. Conclusion; Finding of this study showed significant correlation between the CBSE and CPIE and revealed that the CBSE is a valid measurement for predicting the failure or success of the students in future. Correlation coefficient and predictive validity in females was more than males. Mean of scores showed no significant difference between both sexes.