Solid-phase microextraction (SPME) was applied to the determination of 7 volatile organic sulfur compounds (VOSCs), which were analysed by gas chromatography–mass spectrometry. The compounds studied were ethyl mercaptan (CH 3 CH 2 SH), dimethyl sulfide ((CH 3 ) 2 S), carbon disulfide (CS 2 ), propyl mercaptan (C 3 H 8 S), butyl mercaptan (C 4 H 10 S), dimethyl disulfide ((CH 3 ) 2 S 2 ) and 1-pentanethiol (C 5 H 12 S). Temperature and time conditions of SPME extraction were optimised and the method was validated, with good linearity in a calibration range between 0.1 and 1000μgm −3 . Method detection limits ranged between 0.01 and 0.08μgm −3 and method quantification limits were between 0.10 and 0.25μgm −3 , allowing real samples taken from several different areas of a sewage treatment plant to be analysed. Repeatability of the method between samples went from 5.6% for pentanethiol up to 14.2% for carbon disulfide, and concentrations of total target compounds were found between 18 and 529μgm −3 , depending on the sampling site.