Pusillimonas sp. T7-7 is a diesel oil-degrading cold-tolerant bacterium isolated from the benthal mud of a petroleum-contaminated site in Bohai Sea, China. We present here the complete genome sequence of T7-7. Genome analysis revealed many features of typical marine bacteria, including the absence of intact sugar metabolic pathways, the presence of glyoxylate and gluconeogenesis pathways, and the abilities for nitrate assimilation and denitrification, as well as sulfate reduction and sulfite oxidation. The presence of novel genes for the degradation of diesel oils was suggested.