Micromachining processes have become more imperative in this modern era of miniaturization. Micro-EDM (μEDM) is an excellent micromachining process capable of producing microholes and microfeatures in all electrically conductive materials, irrespective of their mechanical properties. μEDM is a proven process for producing microholes. The quality of microholes is imperative in many applications. The aim of the present study is to investigate the role of capacitance and voltage in determining the perfection of microholes edges that machined using die sinking μEDM by applying image processing techniques. The experimental results reveal that the capacitance significantly influences circularity more than open circuit voltage. The quality of the microholes is also affected by flushing force of dielectric fluid and tool adhesion. Best circularity was achieved with capacitance values between 0.001-0.00001 μF and voltage between 80-100. Discharge energies greater than 50 μJ gradually reduce the quality of microhole edges. © 2013 Copyright Taylor and Francis Group, LLC.