An method and apparatus for estimating a time delay of a GPS receiver in a hybrid navigation system is disclosed. In the hybrid navigation system including the GPS receiver and a DR system, a time difference between a time, at which a velocity measured by the DR system exceeds a reference velocity, and a time, at which a velocity measured by the GPS receiver exceeds the reference velocity, is measured to calculate the time delay of the GPS receiver, so that a GPS/DR system having a loosely-coupled structure which considers the time delay can be realized. Further, in the system, when a vehicle moves from a GPS reception area to a non-reception area and a GPS/DR system mode changes into a DR system mode, an initial velocity value can be estimated while a time delay is considered for a DR system. Furthermore, since a velocity measurement apparatus for vehicles designed in accordance with the apparatus and the method has a performance superior to a velocity measurement apparatus for vehicles in the prior art, it can ultimately contribute to the position estimation accuracy of a position measurement apparatus for vehicles.