In this paper a three-dimensional thermal model of an induction motor is presented. Excepting for providing a more accurate representation of the problem, the proposed model can also reduce computing costs. The finite element method is used to solve the three-dimensional steady-state and/or transient heat flow equation which describes the thermal model, A temperature-time method is employed to evaluate the distribution of loss in various parts of the machine, Using these loss distributions as an input for finite element analysis, more accurate temperature distributions can be then obtained. The validity and accuracy of the proposed method are checked by comparing the results with those obtained from test.