Utilization of biomass gasification technology is not widely adopted due largely to tars contained in the product gas that pose serious problems, especially in engine use. In this paper, a laboratory scale plasma system for light tar cracking was developed. The system was based on non-equilibrium plasmas generated from two gliding arc plasma in series. Light tar components were represented by naphthalene in nitrogen flow, generated at constant rates between 130 - 690 mg/m 3 Destruction efficiency and specific energy use were evaluated. It was found that destruction efficiency in the range of 70 - 95% could be achieved with a simple, single stage reactor. Plasma assisted tar decomposition was found to increase with applied electrical energy. Complete destruction ( > 99%) of light tars was obtained with the two-stage, gliding arc plasma system with applied electrical energy of about 1.8 - 2.9 kWh/m 3 . © 2010 The Berkeley Electronic Press. All rights reserved.