A new two-step hybrid technique (hybrid) has been developed to estimate the earthquake ground motion in three-dimensional (3-D) local models excited by external sources. The main use of the technique is fast evaluation of site effects and seismic hazard because our technique needs less computer memory and time than all-in-one source-path-site computational methods. The first step of the hybrid requires an arbitrary 3-D method (e.g., finite difference (FD), discrete wave number, ray, or analytical solution) to compute three-component excitation on a grid box surrounding a site of interest. A particular excitation contains information on the source and path effects and is saved on disk as a time history. Depending on the method used, the first step may also contain nonplanar topography. The second step (3-D FD) employs local structure and topography inside the excitation box and a procedure that exactly couples the first step results with the second step. The speedup of the hybrid method is made possible through the computation of the excitation (saved on disk) in the first step and the use of FD on irregular grids in the second step of the hybrid. The second step computational model can be just a small spatial fraction of the original source-path-site model. A practical parameter study example of a point double-couple source and regional topography model (applied in the first step) with a local low-velocity basin structure and ridge (both applied in the second step only) is presented.