The paper focuses on the stability of chatter vibrations and tool wear prediction. Chatter-free (stable) cutting parameters are obtained analytically for a sharp and a worn tool considerations and stability lobes of an orthogonal turning operation are constructed using simulations. The effects of the tool wear on chatter vibrations have been studied widely, but the study of the effects of chatter vibration on tool life is very limited. Tool wear tests are mainly conducted under stable cutting conditions, which really cannot explain the wear behaviour under vibratory cutting conditions. An attempt is made to predict the wear and life of a turning tool under chatter vibrations. A tool wear equation is derived which investigates the effects of self-excited chatter vibrations on tool wear in order to predict the tool life. This new tool wear equation clearly indicates that the tool wear increases very rapidly in the presence of chatter. The proposed analytical model and the tool wear equation have been validated with the orthogonal turning experimental results. © Institution of Engineers Australia, 2013.