Sphingomonas paucimobilisBPSI-3 was previously isolated from a mixed microbial consortium growing on biphenyl as the sole source of carbon and energy. Transformation of 4 -chlorobiphenyl (4CBP) was demonstrated by this strain, although little or no growth was observed. In minimal salts medium supplemented with 4CBP or bromobiphenyl and dextrose, yellow coloured product(s) were rapidly formed. Gas chromatography – mass spectrometry (GC–MS) revealed single ring N-heterocyclic compounds that were identified as halopicolinic acids. We believe this to be the first report of such compounds being formed via biological transformation of halobiphenyls. A mechanism is proposed for their formation.Key words: halobiphenyl degradation, halopicolinic acid,Sphingomonas paucimobilisBPSI-3, bioremediation.