The parallel code is constructed by building standard PVM messagepassing calls into an existing serial code. Very few modifications are required to the original algorithm because the parallel model simply farms out individual shot records to a number of machine processing elements (PE's) that are each running an independently spawned copy of the migration code. This simple approach to parallelism allows large 3D seismic surveys to be migrated in a fraction of the time normally required by the equivalent serial code on a single-PE computer. The PVM model can be used to port serial codes to different types of parallel machines with minimal development effort. A description of the parallel model is shown, along with benchmark performance results for code versions written for a workstation cluster and a Cray T3D, using a subset of a full 3D seismic survey as test data.