Objectives: 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.

Methods: The methodology was based on the Ergonomic Behavior Sampling (EBS), and performed using ELECTRE method. In this study 1147 behaviors were observed.

Results: The results indicated that 43.6% of workers’ 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.

Discussion: Findings declare high number of unergonomic behaviors. Catastrophic consequences of accidents in petrochemical industry necessitate paying more attention to workers’ ergonomic behaviors in the workplace.