Occupational exposure to ethylene oxide was assessed among the workers remaining in direct contact with ethylene oxide or with ethylene oxide-sterilized instruments in 13 hospitals located in the city of Lódź and its suburbs. Individual dosimetry and stationary sampling methods were employed. The samples collected from the occupational environment were analysed by gas chromatography with mass detection. The analytical method enabled determination of low ethylene oxide concentrations in the presence of the accompanying chemicals, such as ethyl alcohol, isopropyl alcohol, ethyl ether and isoflurene. In total, 227 determinations were made, and ethylene oxide at concentrations above 0.01 mg/m3 (which was the detection limit of the method) was found to be present in 164 samples. The ethylene oxide levels were found to vary widely, from lower than 0.01 TLV to several hundred times the TLV value.