Machinabihty assessment of a high strength steel was carried out using uncoated and coated inserts. The material investigated was steel EN24T/817M40T 277 (BHN). The object of this assessment is to generate reliable machining data in terms of tool life, cutting force and surface finish in relation to cutting speed, feed rate and depth of cut. During this research cutting tests were carried out by using both one variable-at-a-time and design of experiment approaches. For one-variable-at-a-time experiments, cutting forces, tool life and surface finish were measured. In these tests, the cutting speed, feed rate and depth of cut were varied to study their effects on the tool life, cutting forces and surface finish. With the design of experiment approach, the combined effects of the cutting variables on the machining responses were investigated. Using the mathematical models for different responses, a computerised machinabihty data base system was developed to facilitate the optimum selection of cutting parameters. The selection of cutting parameters is applicable for EN24T/817M40T steel 817.