Purpose: During machining operation, friction between workpiece-cutting tool and cutting tool-chip interfaces result high temperature on cutting tool. The effect of this generated heat affects shorter tool life, higher surface roughness and lowers the dimensional sensitiveness of work material. This result is more important when machining of difficult-to-cut materials, due to occurrence of higher heat. Design/methodology/approach: Different methods have been reported to protect cutting tool from the generated heat during machining operations. The selection of coated cutting tools are an expensive alternative and generally it is a suitable approach for machining some materials such as titanium alloys, heat resistance alloys etc. Another alternative is to apply cutting fluids in machining operation. They are used to provide lubrication and cooling effects between cutting tool and workpiece and cutting tool and chip during machining operation. Hence the influence of generated heat on cutting tool would be prevented. Findings: As a result, important benefits would be achieved such longer tool life, easy chip flow and higher machining quality in the machining processes. The selection of cutting fluids should be carefully carried out to obtain optimum result in machining processes. Various factors are affecting the selection of cutting fluid type in machining operation such as type of workpiece materials, cutting tool material and the method of machining processes. Research limitations/implications: In this study, the selection of cutting fluids for machining processes was examined. The effects of workpiece material, cutting tool and machining process type were determined in detail. Originality/value: In this study, the studies about cutting fluid application in machining processes have been evaluated. The selection criteria of cutting fluids have been examined. Suitable cutting fluids for various material machining processes have been determined according to cutting tool materials.