In this study, a novel Pandoraea sp. strain WL1 capable of mineralizing p-xylene as sole carbon and energy source was isolated from the activated sludge of a pharmaceutical wastewater treatment plant. A nearly complete degradation of 16.6∼99.4mgL−1p-xylene in the liquid-phase was achieved within 6∼18h accompanied by 15.9∼56.3mg dry cell weight (DCW)L−1 for bacterial growth. A complete pathway for p-xylene degradation by strain WL1 was presented through identification of a major intermediate (p-toluic acid) and final products (2.193gCO2gp-xylene−1 of CO2 production and 0.215gDCWgp-xylene−1 of bacterial yield). Kinetics of bacterial growth and p-xylene degradation were evaluated using Haldane–Andrews model and pseudo first-order model, respectively. Furthermore, a biotrickling filter (BTF) was employed to evaluate the application of strain WL1 on the removal of gas-phase p-xylene under gas flow rates of 0.41∼1.98m3h−1 for inlet loading rates of 5∼248gm−3h−1. The BTF inoculated with strain WL1 proved to be robust against fluctuations of gas flow rates and inlet p-xylene concentrations. All the results obtained highlight the potential of strain WL1 for the treatment of p-xylene.