This study focused on using the Taguchi technique to optimize the process parameters in drilling of AISI D2 steel with carbide drills to minimize the surface roughness (Ra) and thrust forces (Ff). The drilling experiments were conducted on a CNC vertical machining centre according to the L18 experimental design. Uncoated drills were classified into three groups: untreated (U), cryo-treated (CT) and cryo-treated and tempered (CTT). The experimental results showed that the CTT drills exhibited the best performance in terms of Ra and Ff due to the improved wear resistance of carbide drills after the cryogenic treatment and tempering. As a result of analysis of variance (ANOVA), it was found that the most influential parameter on both Ra and Ff was the feed rate, with percentage contributions of 66.97% and 80.07%, respectively. The results showed that the Taguchi technique is a powerful method to optimize the process parameters in drilling of tool steel.