This study experimentally investigates the effects of machining parameters on tool life and surface roughness during the CNC turning of C65 steel under dry cutting conditions. The study aims to determine the optimal machining parameters, namely cutting speed, feed rate, and depth of cut, to enhance machining performance while maintaining acceptable surface quality and extending tool life. Achieving these objectives is expected to improve manufacturing productivity and reduce overall machining costs. A structured L9 orthogonal array comprising nine machining trials was employed to systematically investigate the selected machining conditions while minimising the number of experimental runs. Tool life was evaluated in accordance with ISO 3685:1993 using a flank wear criterion of VB = 0.3 mm, whereas surface roughness (Ra) was measured to assess the quality of the machined surface. The turning experiments were conducted under dry cutting conditions on a CNC lathe using single-point carbide inserts. The results revealed that cutting speed was the most influential factor affecting tool life. The longest tool life of 4.6 min was achieved at 1000 rpm, 0.22 mm/rev feed rate, and 2.0 mm depth of cut, whereas the shortest tool life of 0.9 min occurred at 1700 rpm and 0.30 mm/rev feed rate. Surface roughness was primarily governed by feed rate, lower feed rates producing significantly smoother surfaces. The findings demonstrate that the appropriate selection of machining parameters can substantially improve tool performance and surface finish during CNC turning of C65 steel, providing practical guidance for industrial machining applications.................... Keywords:................C65 Steel, CNC turning, Tool life, Surface roughness, ISO 3685:1993, Flank wear, Dry machining.