Samira S Bamuhair,1 Ali I Al Farhan,1,2 Alaa Althubaiti,1 Saeed ur Rahman,1,2 Hanan M Al-Kadri1,3 1College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, 2Department of Family Medicine and Primary Health Care, 3Department of Obstetrics and Gynecology, King Abdulaziz Medical City, Riyadh, Saudi Arabia Background and aims: Information on the effect of students' class attendance on examination performance in a problem-based learning medical curriculum is limited. This study investigates the impact of different educational activities on students' academic performance in a problem-based learning curriculum. Methods: This is a retrospective cohort study conducted on the cardiology block at the College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia. All students who undertook the cardiology block during the academic year 2011–2012 were included. The students' attendance was measured using their overall attendance percentage. This percentage is a product of their attendance of many activities throughout the block. The students' performance was assessed by the final mark obtained, which is a product of many assessment elements. Statistical correlation between students' attendance and performance was established. Results: A total of 127 students were included. The average lecture attendance rate for the medical students in this study was found to be 86%. A significant positive correlation was noted between the overall attendance and the accumulated students' block mark (r=0.52; P<0.001). Students' attendance to different education activities was correlated to their final mark. Lecture attendance was the most significant predictor (P<0.001), that is, 1.0% increase in lecture attendance has predicted a 0.27 increase in students' final block mark. Conclusion: Class attendance has a positive effect on students' academic performance with stronger effect for lecture attendance compared to attendance in other teaching modalities. This suggests that lecture attendance is critical for learning even when a problem-based learning medical curriculum is applied. Keywords: class attendance, academic performance, problem-based learning