Tehran University of Medical Sciences International Journal of Occupational Hygiene 2008-5109 10 1 2018 02 06 33 38 EN Seyed Akbar Sharifian Center for Research on Occupational Diseases, Tehran University of Medical Sciences, Tehran, Iran Omid Aminian Center for Research on Occupational Diseases, Tehran University of Medical Sciences, Tehran, Iran Sahar Eftekhari Center for Research on Occupational Diseases, Tehran University of Medical Sciences, Tehran, Iran Hossein Mohseni HSE Management auto plant group, Tehran, Iran Seyed Amir Hossein Morshed Zadeh Center for Research on Occupational Diseases, Tehran University of Medical Sciences, Tehran, Iran 2017 09 04 2017 12 18 Sickness absenteeism is a major problem among organizations and healthcare units, causing loss of workhours and reduced productivity in workplaces. Previous studies have shown that several factors are associated with sickness absenteeism, including social conditions, workplace/organizational conditions, and employees’ characteristics. Other studies have shown that psychological disorders, such as depression and anxiety, as well as musculoskeletal disorders are the main causes of medical absenteeism. The present study was designed to investigate sickness absenteeism in the employees of an auto plant in order to evaluate the occupational health of the employees based on the basic indicators of absenteeism. An institutional-based cross-sectional study was organized in 2016 to evaluate the intensity of sickness absenteeism and its associated factors among auto plant employees in Tehran, Iran. Stratified sampling and simple random sampling techniques were used to select the participants. Data was collected from questionnaires, medical records, and employees’ attendance system. Multivariable analyses were employed to investigate the effect of the explanatory variables on the dependent variable. The frequency of medical absenteeism among employees was 11.3%. According to the results, 26.8% of medical absenteeism was more than 15 days. Smoking and workplace groups were significantly associated with sickness absenteeism. Our study found that smoking and working in the Trunk 1 Department of the auto plant were significant risk factors for sickness absence among employees. In general, absenteeism is a complex and multifactorial phenomenon in real need of evaluation to identify and control its effective factors https://ijoh.tums.ac.ir/index.php/ijoh/article/view/310