Introduction: This study was to evaluate the vicarious or secondary post traumatic stress disorder (PTSD) in Sardasht chemical warfare victims' wives. Method: In this descriptive cross-sectional study, 306 persons were analyzed in two case (150 wives of Sardasht chemical warfare victims) and control (156 wives of Sardasht normal families) groups. A 39-query Mississippi questionnaire was filled for each person in order to evaluate the severity of PTSD. Results: The total Mississippi degree was 128.68±12.67 in chemical warfare victims' wives and 111.27±21.21 in control group. The prevalence and severity of PTSD in chemical warfare victims' wives were sensibly more than the control group. The total Mississippi score in chemical victims (case group's husbands) was higher than normal people (control group's husbands). Conclusion: According to high prevalence and severity of this disorder in chemical warfare victims' wives, it is necessary to follow up and treat the involved cases.