AbstractSince the 1980s, several methodologies have been developed to measure ocean surface wind, waves, and currents using standard marine radars operating at X-band. Today, marine radars are often used operationally to measure the spectral quantities of ocean surface waves. They also have shown to be very useful to measure surface winds and currents as well as bathymetry. Within this chapter, a brief review is given on the most common methods utilized to retrieve wind, currents, and waves. Therefore, a brief introduction on ocean surface backscattering at grazing incidence, as well as the physical basis of the applied methods, is given. Furthermore, the main processing steps of the retrieval methods are introduced and applied to some examples. To show the overall performance of the methodologies, the radar-retrieved parameters are compared to well-accepted measurement techniques. Finally, the limitations of the different radar measurement techniques are discussed.