In the present work, the performances of the nanostructured TiAlN, AlCrN, TiAlN/AlCrN coated are evaluated by comparing the machining performance with uncoated carbide cutting tool by conducting the machining studies on En24 alloy steel. Taguchi’s experimental design is used to design the turning experiments and fix the turning parameters, such as the cutting speed (V), feed rate (f) and depth of cut (d). The signal-to-noise ratio and anova were used to investigate the effects of the machining parameters and their contribution to the tool wear and surface roughness. The results show that the nanostructured TiAlN/AlCrN coated insert has developed minimum flank wear and shown minimum surface roughness on the machined surface, compared to the TiAlN, AlCrN coated and uncoated tools. The cutting parameters in which the TiAlN, TiAlN/AlCrN coated and uncoated inserts have shown lesser tool flank wear and better surface finish of the workpiece are identified. For the TiAlN tool, the better machining parameters are, cutting speed = 160 m/min, feed rate = 0.119 mm/rev, and the depth of cut = 1.0 mm. For TiAlN/AlCrN, the better machining parameters are, cutting speed = 160 m/min, feed rate = 0.318 mm/rev, and the depth of cut = 0.3 mm, and for the uncoated tool, the cutting speed = 100 m/min, feed rate = 0.318 mm/rev, and the depth of cut = 1.0 mm is the best machining condition. But for the AlCrN tool the minimum tool wear was obtained, when the cutting speed = 40 m/min, feed rate = 0.477 mm/rev, and the depth of cut = 1.0mm and better surface finish of the work-piece was obtained, when the cutting speed = 160 m/min, feed rate = 0.119 mm/rev, and the depth of cut = 1.0 mm. © 2016, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.