Minimum quantity lubrication is a possible solution for the optimum lubrication system. This is an alternative between wet and dry machining. In minimum quantity lubrication system, a very small amount of lubricant is used. In this paper, the studies about minimum quantity lubrication was examined. the selection criteria of cutting fluid have been examined. various MQL systems for machining. choosing suitable lubricants for various machining operations have been determined according to cutting tool materials.