For effective toluene degradation, the effects of a nitrogen source were studied with Pseudomonas putida BZ912, which was isolated from crude oil contaminated soil and is capable of degrading VOC. Two nitrogen sources, ammonia and nitrate, showed different effects on specific growth rates (0.25 hr.1 and 0.12 hr.1, respectively), biomass yields (0.56 vs. 0.39) and specific toluene degradation rates (0.51 hr.1 vs. 0.26 hr.1). Under the resting cell conditions, the cells pre-cultured in the ammonia-containing medium showed higher specific toluene degradation rate than that in nitrate-containing medium (0.045 hr.1 vs. 0.038 hr.1). Ammonia as a nitrogen source was effective for degradation in high toluene concentration because high cellular biomass was accomplished. Nitrate showed slow growth rate compared to ammonia. The resting cell conditions demonstrated that it was able to degrade toluene efficiently without increasing biomass. These conditions could be a solution for degrading VOC after high cellular biomass was obtained in a biofilter. By changing the nitrogen source and the growth conditions according to the toluene concentration, the control of cell biomass and the desired removal capacity were accomplished.