The stiffness of the base layer is an important parameter for designing the pavement thickness needed to support traffic loadings. It is normally related to the California bearing ratio (CBR). Currently, the CBR could be obtained from laboratory and field testing using Dynamic Cone Penetrometer (DCP). These methods are time consuming, destructive and costly. The spectral analysis of surface waves (SASW) method is hereby introduced as an in situ non destructive seismic technique to obtain the CBR and DCP values from the measurement and correlation of the dynamic properties of the pavement system. The relationship between the shear wave velocity and dynamic stiffness of the SASW were found to correlate well with DCP and CBR. The empirical correlations of CBR to dynamic stiffness in terms of elastic modulus were found to be similar to the correlation suggested by Shell (1978). Preliminary analysis also indicated that the empirical model was useful for predicting pavement base layer modulus.