Objective: To evaluate the effect of using the Digital Histology Catalogue as an adjunct to conventional microscopic tissue slides on the examination score of undergraduate medical students. Study Design: Descriptive Observational Study. Place and Duration: CMH Multan Institute of Medical Sciences from 2nd January 2017 to 28th February 2020. Methodology: Data was collected retrospectively from the summative module exam results of 1st and 2nd-year MBBS for Batch 2018-23 (Group A) and Batch 2017-22 (Group B). Group A was introduced to the online histology catalogue in their 2nd year of MBBS. In contrast, Group B was not introduced to any such intervention. Modular results of 1st and 2nd-year MBBS were compared for both Group A and B. To further support our results, modular results of Group A and Group B were compared with each other, for 1st-year MBBS (when no group was introduced to online catalogue) and 2nd-year MBBS (when only Group A was introduced to the online catalogue). Results: For Group A, students scored higher marks in module exams of Second Year (after the intervention) as compared to their First Year (p <0.001). There was no significant difference between the mean marks of two years for Group B. Although students of both groups had similar marks in their first-year MBBS, during their second year of study, Group A (exposed to intervention) performed better as compared to Group B (p <0.001). Conclusion: Self-Learning by online digital histology catalogue had a positive effect on the academic performance of the undergraduate medical students in their summative histology practical exams. [ABSTRACT FROM AUTHOR]