Fatigue performance of machined components, particularly Ni-based alloys that are extensively employed in aero engine parts, is greatly influenced by the surface roughness parameters. Various superior mechanical and chemical properties make Ni-based alloys convenient for heat resistant applications However, it also makes them difficult to machine. In this context, this study presents the details of an experimental investigation carried out on machining of Inconel 625 under dry conditions to analyze the impact of machining parameters on Ra, Rz and Rsk, the three surface roughness parameters. Results of the study revealed that superior average surface roughness (0.1–0.4 µm) could be obtained at a feed per tooth of 0.04–0.075 mm/tooth and cutting speed of 60 to 100 m/min. The minimum value of Rsk (0.1055 µm) was found at the cutting speed between 77 and 90 m/min and the radial depth of cut between 0.2 and 0.58 mm. It was also observed that a considerable value of Rsk could be obtained at any level of feed per tooth and lower value of radial depth of cut. Results of the interaction of process parameters showed a moderate value of Rz at a lower level of feed (0.04–0.08 mm/tooth), under any level of radial depth of cut. The highest value of Rz (5–6 µm) was found at a high level of feed per tooth and radial rake angle.