A method for determination of residual styrene monomer and other volatile organic compounds in expanded polystyrene (EPS) was developed using HS SPME and gas chromatography with FID. The extraction products were identified by GC/MS. Good reproducibility of the measurements with RSD values between 3.2–3.6% was achieved by extraction using a 75 μm Carboxen-Polydimethylsiloxane fiber at 60°C with 15 min sample sonication. The contents of residual styrene monomer in two samples of EPS were 153.2 and 65.7 mg/kg, respectively. Other compounds identified in EPS were pentane, benzene, toluene, ethylbenzene, isomers of xylene, n-propylbenzene, 1,2,4-trimethylbenzene, o-methylstyrene, benzaldehyde, benzyl alcohol, and acetophenone.