True-amplitude migration is a particular form of mi- gration of the Kirchhoff type. A weighted diffraction stack is performed using a specific weight function. True-amplitude migration can be employed to obtain a reconstruction of the source pulse that is proportional to the reflection coefficient of the target reflector. In most cases dynamic ray tracing has to be applied to compute the proper weight functions. This makes it a very time consuming process. We propose a method to compute migration weights using the ray propagator. This matrix contains all necessary information and can be determined directly from traveltimes.