The continuous surface wave (CSW) test is a seismic technique for determining ground stiffness by measuring the velocity of Rayleigh wave propagation along the ground surface. A sinusoidal force is generated by a shaker placed on the ground surface and the response is detected by an array of geophones also at the surface. Measurements are made for a range of shaker frequencies thereby allowing a profile of stiffness with depth to be established. The continuous surface wave test is performed relatively quickly and is less expensive than conventional stiffness measurement techniques; in addition it is non-intrusive and non-destructive thus making it attractive for civil engineering applications. This paper describes the continuous surface wave test, the execution of the test, analysis of the data as well as interpretation of the results. Calibration results as well as typical results from full scale field tests are presented.