en پژوهشي Original Research Articles <p style="text-align: justify;"><strong>Objectives: </strong>This study aimed to evaluate and analyze the ergonomic behaviors order to select the best work shift group in an Iranian petrochemical Company, in 2010.</p> <p style="text-align: justify;"><strong>Methods:</strong> The methodology was based on the Ergonomic Behavior Sampling (EBS), and performed using ELECTRE method. In this study 1147 behaviors were observed.</p> <p style="text-align: justify;"><strong>Results:</strong> The results indicated that 43.6% of workers&rsquo; behaviors were unergonomic. The most frequent unergonomic behavior was amusing of legs while load lifting with 83.01% of total unergonomic behaviors observations. Using ELECTRE method, most effective shift group and least attractive alternatives for intervention were selected in the company.</p> <p style="text-align: justify;"><strong>Discussion:</strong> Findings declare high number of unergonomic behaviors. Catastrophic consequences of accidents in petrochemical industry necessitate paying more attention to workers&rsquo; ergonomic behaviors in the workplace.</p> Ergonomic behavior, Ergonomic behavior sampling, ELECTRE 15 20 http://irj.uswr.ac.ir/browse.php?a_code=A-10-1-67&slc_lang=en&sid=1 Mohammad Khandan No Department of Ergonomics, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Maryam Maghsoudipour maryammaghsoudi@yahoo.com Yes Department of Ergonomics, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Shahram Vosoughi No Department of Health Sciences, Faculty of Health, Safety and Environment, Shahid Beheshti University of Medical Sciences, Tehran, Iran.