Introduction: Multiple choice questions are the most common and objective test in medical science education. The aim of this study is to determine effectiveness of faculty development program on quality of residency exams in medical school of Qazvin University of Medical Sciences (QUMS) in Iran.Methods: This was a Quasi-experimental study (before & after intervention).Faculty development program was conducted in three phases: First, a book titled ”design and evaluation of multiple choice questions “was given to all departments. All questions from residency exams of QUMS for 7 specialty programs in 2013 (there were 150 questions for each specialty, totaling 1050 questions) were structurally evaluated using a valid and reliable checklist based on Millman principles. In the second phase, feedback of survey result were given to all 7 groups. Finally, educational workshops, one for each department were organized before residency exams in 2014. Data related to questions designed by faculties who had participated in the interventional workshop were analyzed using statistical T-test and ANOVA.Results: Overall, 2100 questions related to 7 departments including: pediatric, surgery, internal medicine, cardiology, psychiatry, obstetrics and gynecology, anesthesiology were analyzed. Findings showed that poorly structural questions in 2013were 0.58±0.02, and in 2014, were 0.44± 0.02. Using a t-test of independent groups showed significantly different before and after training (p<0.001).Conclusion: Current study showed that faculty development programs are significantly effective in promoting and it needs to be developed.