Tehran University of Medical Sciences International Journal of Occupational Hygiene 2008-5109 3 1 2011 06 15 38 42 Alireza Choobineh Research Center for Health Science, Shiraz University of Medical Sciences, Shiraz, Iran. Ahmad Soltanzadeh Occupational Health Department, School of Health and Nutrition, Shiraz University of Medical Sciences, Shiraz, Iran Hamidreza Tabatabaee 3Epidemiology Department, School of Health and Nutrition, Shiraz University of Medical Sciences, Shiraz, Iran Mehdi Jahangiri Occupational Health Department, School of Health, Tehran University of Medical Sciences, Tehran, Iran Masoud Neghab Occupational Health Department, School of Health and Nutrition, Shiraz University of Medical Sciences, Shiraz, Iran Solayman Khavaji HSE department, Pars petrochemical region, Asalooyeh, Iran 2015 10 04 Shiftwork that affects diverse aspects of human life is arranged in various schedules. The main purpose of this study was to compare psycho-social problems among employees working in different 12-hour shift schedules of Iranian petrochemical industries. This cross-sectional study was carried out at eight petrochemical companies in Asalooyeh area. The study population consisted of 549 shift workers. Data on personal details, shift schedule, and adverse effects of shift work were collected by anonymous questionnaire. Statistical analyses were performed using SPSS, version 11.5. Among 549 studied shift employees, 39.6% worked in 4N-7D-3N-7R (4 nights- 7 days- 3 nights- 7 rests), 29.1% in 7N-7 D-7R, and 31.3% in 7D-7N-7R schedules. Psychosocial problems among 7D-7N-7R schedule shift workers were significantly more prevalent than other schedules (p<0.05). Prevalence rates of psychosocial problems among all schedules were high, but odds ratios of problems among 7D-7N-7R schedule shift workers were significantly more than those of the two other ones were. This schedule should be changed therefore to decrease such problems. https://ijoh.tums.ac.ir/index.php/ijoh/article/view/32 https://ijoh.tums.ac.ir/index.php/ijoh/article/download/32/32