The performance of 1,1,1,2-tetrafluoroethane or HFC-134a decomposition and the formation of byproducts in a dielectric barrier discharge plasma reactor were studied with different packing systems such as a-Al 2 O 3 (porous and nonporous), c-Al 2 O 3 (porous) and ZrO 2 (nonporous). Experimental variables such as reactor temperature, initial HFC-134a concentration and oxygen levels were chosen for the performance analysis. Among the packing systems, the porous c-Al 2 O 3 and a-Al 2 O 3 decomposed HFC-134a much more effectively than the nonporous a-Al 2 O 3 and ZrO 2 . The combination of the plasma with the porous cAl 2 O 3 was found to cover a wide range of initial concentration. The decomposition efficiency tended to increase with the addition of oxygen up to 2 %, but further increase in the oxygen led to a decrease. As well as carbon oxides (CO 2 and CO), significant amounts of unwanted byproducts such as COF 2 and CF 4 were also identified in the effluent gas with the nonporous a-Al 2 O 3 and ZrO 2 . On the contrary, with the porous c-Al 2 O 3 and a-Al 2 O 3 , such unwanted byproducts were considerably suppressed, enhancing the formation of CO 2 and CO.