Traditionally, the process for converting CH4 into syngas (CO and H-2) is usually carried out at high temperature with catalysts. In this study, a new approach using a lab-scale radio frequency (rf) plasma reactor is made at room temperature with a single-step process. The major factors that affected the conversion and selectivity were examined by the fractional factorial experimental design method. Experimental results indicated that the higher methane conversion was achieved at either a higher applied power or inlet O-2/CH4 molar ratio (R), while the simultaneous higher selectivities of H-2 and CO were obtained at a lower R. At [CH4](in) = 33.3% and 4000 N/m(2), the better operating conditions were at R = 1 with 130 W. The methane conversion equaled 80.1%, and the selectivities of H-2 and CO reached 92.6% and 74.0%, respectively, with a H-2/CO molar ratio of 2.5.