This study examines the use of wire electrical discharge machining (WEDM) in machining polycrystalline silicon with resistivity of 2-3 Omega cm. The effects of different WEDM parameters on cutting speed, machining groove width, and surface roughness are explored. Experimental results indicate that open voltage is the critical parameter in breaking the insulation of polycrystalline silicon, and that pulse-on time has the greatest influence on cutting speed. Other machining factors, such as flushing rate, have no significant effect on cutting speed but do nonetheless improve machining groove width and surface roughness. In addition, strengthening wire tension reduces vibration of the wire electrode, which also helps improve machining groove width. The experimental results show that WEDM can be practically applied to machining polycrystalline silicon. Hence, applications of WEDM to manufacturing of solar cell can lead to significant enhancement in production efficiency.