The unconventional wire electric discharge machining technology (WEDM) is widely used in many industries, which is why there is a permanent emphasis on increasing the quality of suchmachined surface. The aim of this study was to carry out a design of experiment (DoE) to reduce the surface qualit yparameter Pq. During the 33-round experiment, the input factors – machine setting parameters, such as gap voltage, pulse on time, pulse off time, wire speed, and discharge current, were changed. Subsequently, Pq – root mean square deviation of the primary profile and Pa – arithmetic average of the primary profile were evaluated on the machined surfaces of pure aluminium. By using DoE, the setting of the machine’s parameters was designed in order to achieve the highest possible surface quality.