Background: Student absenteeism refers to the frequent absence from classes without any good reason and thought to be the primary concern in health profession education worldwide mainly in medical school. Methods and Material: This study is a cross sectional design conducted in 152 medical students of King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Saudi Arabia. A self-reported questionnaire was used to determine absenteeism behavior, contributing factors of absenteeism, and level of satisfaction of medical students towards the medical program of the university. Adapted questionnaire from Timmins and Kaliszer (9) was also utilized to examine factors of stress among medical students. Descriptive statistics, linear correlation and Pearson correlational coefficient utilizing SPSS v22 for the analysis of data. Results: A total of 143 (92.76%) participated in the study. 104 or 72 % were male, and 28% were female with mean age of 22.5 (±2.02) and a mean GPA of 4.4 (±0.4). 77 (53.8%) of students were absent for 5 times or more in lectures/basic and clinical sciences sessions and clinical diagnostic sessions. These absences are mainly because of study (n=36, 25.2%) and course dissatisfaction (n=32, 22.4%). However, only 3 (2.1%) who had an absence for 5 times or more in Problem Based Learning (PBL) sessions. These absences in PBL sessions are mainly because of sleep (n=11, 7.7%) and family commitments (n=10, 7.0%). There is an inverse correlation between absenteeism and academic performance. Conclusion: Absenteeism has a negative impact on the academic performance of medical students.