Background: 1-Chloro-2,3-epoxypropane, known as epichlorohydrin (ECH), is a colorless liquid used in the production of epoxy resins, synthetic glycerine, elastomers, glycidyl ethers, surfactants, polyamide-epichlorohydrin resins and others. Epichlorohydrin may cause cancer. The aim of this study was to develop a new method for determining concentrations of ECH in workplace air in the range of 1/10–2 values of the maximum admissible concentration (MAC). Material and Methods: The paper presents a method for the determination of ECH in workplace air using a gas chromatograph coupled with a mass spectrometer (GC-MS). The developed method is based on the adsorption of ECH on an activated charcoal, extraction with acetone, and a chromatographic analysis of the resulting solution. Results: The method developed makes it possible to determine ECH in the concentration range of 0.1–2 mg/m³, i.e., 1/10–2 values of MAC established in Poland. The limit of detection (LOD) is 0.24 μg/m³ and the limit of quantification (LOQ) is 0.71 μg/m³. Conclusions: The method is characterized by good precision and accuracy; it meets the requirements of the European standard PN-EN 482, and can be used by occupational hygiene laboratories to measure concentrations of ECH in workplace air, with a view to assessing workers’ exposure to this substance. Med Pr. 2020;71(6):715–23