Microbial degradation of thiodiglycol (bis(2-hydroxyethyl)sulfide, TDG) with petroleum-desulfurizing soil bacteria was examined. Among the bacteria tested, several strains belonging to the genera Rhodococcus and Gordonia grew on TDG as the sole sulfur source. The selected strain Rhodococcus sp. strain T09, which was re-identified as R. jostii, showed TDG degradation activity only when grown in the presence of TDG as the sole sulfur source. Repeat batch degradation of TDG by using strain T09 could be continued for over 50h, with a slight loss of activity.