The beta-adrenergic blocking potency of 56 1-substituted ureidophenoxy-3-amino-2-propanols has been analysed in terms of the linear Free-Wilson model. The values obtained for the Free-Wilson coefficients have been correlated with the chemico-physical parameters of the substituents. The preliminary indication given by the Free-Wilson analysis has been confirmed by a quantitative regression analysis, carried out in the frame of the "mixed approach" method.