The dependence of thermal degradation behaviour on vinyl acetate (VA) content of ethylene-vinyl acetate (EVA) copolymers was studied by thermogravimetric analysis (t.g.a.). Among the parameters investigated, the maximum rate of weight loss at the stage of acetic acid evolution was found to have a linear relationship with VA content and to be independent of molecular weight and heating rate. Thus, a new method based on t.g.a. for the prediction of VA content of EVA copolymers is suggested.