We investigated the degradation of biphenyl and identified main degradation products. Biphenyl and 2,3-dihydroxybiphenyl (2,3-DHB) was added to cultivation media to identify whole collection of degradation products of four bacterial strains isolated from long-term PCB contaminated soil (Alcaligenes xylosoxidans and Pseudomonas stutzeri) and long-term PCB contaminated sediment (Ochrobactrum anthropi and Pseudomonas veronii). Cultivation flasks were processed in different time after inoculation to determine biphenyl fission rate. Alcaligenes xylosoxidans was revealed as the most appropriate strain for bioremediation process with the highest biphenyl transformation rate. Biphenyl degradation led to the formation of benzoic acid. However, as the presence of 2-hydroxy-6-oxo-6-phenylhex-2,4-dienoic acid (HOPDA) was not confirmed, the transformation pathway common for many other bacteria is probably modified.