Background and Aim: Ethylene oxide is used as a sterilizing agent in health care industries. The present study aimed to assess and recognize the nature of pulmonary reactions, if any, associated with occupational exposure to ethylene oxide and to investigate the prevalence of dermal, visual, neurologic, reproductive, hematologic, hepatic and renal disorders.Method: Forty exposed and 47 unexposed employees were evaluated. Subjects were interviewed and standard respiratory symptom questionnaire as well as a questionnaire pertaining to symptoms of intoxication with this chemical were administered to them. Furthermore, parameters of pulmonary function were measured during exposure and a few days after exposure ceased. Additionally, blood samples were taken for CBC, liver and kidney function tests. Moreover, atmospheric concentrations of ethylene oxide were determined by gas detector tubes.Results: Respiratory symptoms such as cough and phlegm as well as dermal, visual and neurologic symptoms in exposed workers were significantly more prevalent p£0.05. Furthermore, significant decrements in some parameters of pulmonary function during exposure as compared with the values measured after exposure ceased, were noted. Results of biochemical tests were similar in both groups. Mean atmospheric concentration of ethylene oxide was evaluated to be 1.24±1.5 ppm.Conclusions: The findings of this study indicate that exposure to ethylene oxide even at low concentrations is associated with significant decreases in pulmonary parameters. However, this effect is acute, temporary and reversible. Conversely, exposure to ethylene oxide was not associated with hematotoxic, hepatotoxic and nephrotoxic response, although, dermal, visual and neurologic symptoms were observed.