This paper is focused on optimizing the cutting conditions for the surface roughness, inner-diameter error and roundness obtained in hard turning of an inner ring bore. The hard-turning experiments were conducted on hardened and tempered AISI 52100 bearing rings using the L9 orthogonal array on a CNC lathe. The cutting speed, feed rate and number of the machined part were selected as control factors. The optimum cutting conditions were determined using the signal-to-noise (SIN) ratio. S/N ratios were calculated using the lower-the-better approach. An analysis of variance (ANOVA) was also employed to determine the level of the effect of the control factors for the surface roughness, inner-diameter error and roundness. The statistical analysis showed that the feed rate was the most significant factor for the surface roughness while the cutting speed was the most significant factor for the roundness and inner-diameter error. Finally, the optimum cutting conditions were further confirmed with confirmation tests.