A bacterial strain, SWU-4, capable of using benzothiophene (BT) as a sole carbon and energy source was isolated from a petroleum-contaminated site in Thailand and identified by 16S rRNA gene sequence analysis to be in the genus of Mycobacterium. The strain was Gram-positive, nonspore former, and grew at 50degreesC. Colonies of the strain on nutrient agar were rod-shaped, smooth with a convex surface, slightly mucoid, and yellow pigmented. The thermophilic Mycobacterium sp. strain SWU-4 rapidly degraded 2% (w/v) BT at 50degreesC. Interestingly, this strain was able to degrade a wide variety of organosulfur compounds including thiophene, bromo(alpha)thiophene, and 3-methylthiophene in liquid minimum medium at 50degreesC, which will be beneficial for industrial applications.