This paper presents a new approach to exact timestamping of asynchronous measurements in a multi-sensor setup. In order to improve the performance of a single sensor, driver assistance systems use several different sensors which have different latencies that usually cannot be measured directly. These unknown latencies pose a problem in data association and temporal synchronization. Consequently, a method to estimate or incorporate the latencies is needed in all sensor fusion algorithms in order to derive the real time of a measurement. In this paper a method is described to compensate the sensor latencies even if they cannot be observed directly.