This paper deals with the study of twelve bituminous mixes selected to cover the whole range of mixes for road, airfield and hydraulic work applications. The determination of their stiffness modulus and loss angle under dynamic load, with the aid of a two-point bending machine has led to the following conclusions: (1) the stiffness modulus of the mix (ratio of the stress amplitude to the strain amplitude), at relatively low temperatures and short times of loading, is essentially dependent on: (a) the stiffness modulus of the bitumen binder contained in the mix, under the service conditions, (b) the volume percentages of the different mix components (aggregates, bitumen binder, air). (2) the loss angle (phase lag between the stress and the strain) is mainly influenced by: (a) the bitumen binder consistency, (b) the volume percentage of this binder. From these findings, a method of predicting the stiffness modulus and loss angle has been developed. This method is applicable to all asphalt paving mixtures from filler-bitumen (mastic) mixes to very open (high void) mixes for roads. The stiffness modulus and the loss angle are determined with the aid of two nomographs or a computer programme. /Author/TRRL/