The wearing rate on the beads of diamond wire is the major parameter that effects the cost of a hard rock marble quarry in the diamond wire cutting method. Therefore, it is very important to develop the predictive equations that can be used to assess the wearing on beads during the rock cutting. This study is primarily concerned with this problem. Diamond wire cutting studies in industrial scale were performed at andesitic rocks of different mechanical and physical characteristics. The andesitic rocks are located at Cubuk District of Ankara Province (TURKEY). The wearings on beads in two modes of vertical and horizontal cuttings are evaluated separetely and modelled as function of rock properties, machine and cutting characteristics. Multivariate statistical methods include factor and regression analysis in reduced and unreduced forms. The unreduced model covers all the independent variables. In the reduced model one of the variables that is strongly interrelated (X-2, X-11, X-13, X-16, X-17) is eliminated and the rest is used in the analysis. Reduced and unreduced model equations predicting the wearing of diamond beads in the wire cutting of andesitic rocks are developed.