Drilling is one of the most important machining processes that have been broadly applied in the manufacturing area. In this study, the effect of drill bit temperature on tool life of twist drills in the hard drilling in dry condition process of AISI 4340 high-strength low-alloy steel was investigated numerically and experimentally. In the numerical phase, a 3D finite element model of the hard drilling process was carried out with DEFORM-3D software. During the finite element analysis of the hard drilling processes, the tool temperature at drill bit was numerically obtained and compared with the experimental drill bit temperature. During the experimental phase, the tool life of twist drill is also measured at different machining conditions. At the end of the study, the results showed that there is a good agreement between the experimental and numerical results of tool drill bit temperature. It is observed that the tool life and tool temperature are related to each other. And the tool life can be increased by selecting the most appropriate parameters.