The study aims to evaluate the workers' safety behavior in ail Iranian gas treatment company. The methodology was based on the safety behavior sampling (SBS) technique. After specifying the unsafe behaviors and with reference to the results of a pilot study, a sample of 3248 was determined, with a sampling accuracy of 5% and confidence level of 95%. The results indicated that 26.7% of workers' behaviors were unsafe. The most important unsafe behaviors were awkward postures in working hours with 13.1% of total unsafe behaviors. The results also notified a significant relationship between age and job experience on unsafe behaviors (p<0.001). The relationship between unsafe behaviors and previous accidents records was also significant (p <0.005). The ultimate findings of the study showed that a considerable number of workers' behaviors were unsafe, which is one of the main antecedents of industrial accidents. Considering catastrophic consequences of accidents in gas treatment industry, the results emphasize on diminishing unsafe behaviors and recommend applying behavior-based safety principles. (C) 2007 Elsevier Ltd. All rights reserved.