Work system safety is a function of many factors, besides it is dynamic and complex. There may be relations and dependencies among the safety factors. Therefore, work system safety should be analyzed in a holistic manner. In this study, the faulty behavior risk (FBR) which is significant in work system safety is tried to be determined through analytical network process (ANP) which is an extension of analytical hierarchy process and allows analysis of complex systems. Besides, there are many difficulties and limitations in measuring the faulty behavior factors. For this reason, the weights of factors and sub-factors necessary to calculate the FBR are determined by using fuzzy ANP and by this way it was possible to make better decisions in this process. (C) 2007 Elsevier Ltd. All rights reserved.