The management of odorous emissions from sewer networks has become an important issue for sewer system operators resulting in the need to better understand the composition of reduced sulfur compounds (RSCs). Gaseous RSCs including hydrogen sulfide (H₂S), methanethiol (MeSH), dimethyl sulfide (DMS), carbon disulfide (CS₂), dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) were measured in the atmosphere of selected sewer networks in two major Australian cities (Sydney and Melbourne) during 2011–2012. The RSC concentrations in the sewer air were detected in a highly variable range. H₂S and MeSH were found at the highest concentrations, followed by DMS (39.2–94.0 μg/m³), CS₂ (18.3–19.6 μg/m³), DMDS (7.8–49.6 μg/m³) and DMTS (10.4–35.3 μg/m³). Temporal trends in the occurrence of targeted RSCs were observed and the highest sulfur concentration occurred either in summer or spring, which are typically regarded as the warmer seasons. Statistical significant difference in the magnitude of targeted RSCs was found between samples collected in Sydney and Melbourne.