Introduction:Providing feedback to students is an essential component in medical education and has been shown to improve the students’ learning. The purpose of this study is to evaluate the effect of computer-based immediate feedback on the medical students’ learning in a pharmacology course. Methods:In this prospective intervention study some feedback modules in pharmacology (FMP) were prepared in two topics: the cardiovascular system (CVS) and chemotherapy, using blank templates on “Hot Potatoes” software. The FMP included MC-based questions and two versions were developed: one with feedback (FMP-1) and the other without feedback (FMP-2). The FMP-1 module provided immediate feedback for each option the student chose. The students (n=48) were randomized by computer generated random number table to two groups A and B to receive the module in CVS, i.e., FMP-1 and FMP-2, respectively. A cross-over design was adopted to expose all students to immediate feedback modules. The test scores were compared and feedback was obtained from students and faculty using a validated questionnaire. A focus group discussion was conducted to clarify the issues raised by the students. Results: The module with immediate feedback was much better appreciated by the students than the module without feedback. The students spent more time on FMP-1 (42±7.00 minutes vs 27±12.36 minutes; p<0.001 in chemotherapy and 40±12.11 minutes vs 24±6.01 minutes; p<0.001 in CVS). However, there was no statistically significant difference in mean test scores. The qualitative data collected provided important information on the value of immediate feedback. The students believed that immediate feedback was an excellent way for self-assessment and improved their deeper understanding of content areas. They also felt that it supplemented their traditional learning habits and stimulated them to read more. The students enjoyed its non-threatening nature. Conclusion:Immediate feedback improved the deeper understanding of pharmacology and its relevance to medicine for the two topics although immediate feedback did not improve test scores. Overall, immediate feedback had a positive impact on the students’ self-directed learning.