Introduction: Information on sick leave duration among employees with the first episode of acute coronary syndrome (ACS) throughout the world was limited. The aims of the study were to determine the sick leave duration and its predictive factors among employees diagnosed with the first episode of ACS. Methods: A cohort study was conduct- ed among employees who were admitted to the cardiology centre in the public hospitals in northeastern Malaysia. Data was collected using a designed proforma. The respondents were interviewed, and their medical records were reviewed on the second day of hospital admission. Information on sick leave duration was obtained from sick leave book in the wards. Multiple linear regression analysis was applied to determine the predictive factors for sick leave duration. Results: A total of 78 respondents participated in this study. The mean (SD) age of the respondents was
47.5 (7.31) year old. The majority were male (92.3%), married (94.9%) and had a low level of education (62.8%). The sick leave duration ranged from 4 to 180 days with the median (IqR) of 35.5 (32) days. The predictive factors for sick leave duration were smoking (Adjusted b=20.1, 95% CI: 7.4, 32.8), not attending cardiac rehabilitation after discharge (Adjusted b=19.9, 95% CI: 6.7, 33.6) and presence of complication during admission (Adjusted b=28.6, 95% CI: 15.1, 42.0). Conclusion: The sick leave duration was relatively low and being a smoker, having a complica- tion during admission and not attending cardiac rehabilitation after discharged predicts a longer sick leave duration.