The effects of a cutting tool's chemical composition on wear and tool life are investigated. A series of experiments was carried out using silicon-nitrite-based (Si, Al, O, N) and whisker-reinforced ceramic tools (Al2O3+SiCw) that have two different geometries (square and circular) and three different ISO qualities. For the ceramic tools, a high level of aluminum and germanium caused built-up edge (BUE) formation, while notch wear is considered as a cause of high copper and oxygen levels in whisker-reinforced ceramic tools. Four different tools with two qualities showed the best performance at a cutting speed of 200 m/min. The fact that the whisker-reinforced square-type ceramic tools are subjected to plastic deformation is attributed to the high oxygen level in the cutting tool's structure. (C) 2007 Journal of Mechanical Engineering. All rights reserved.