In this study, the composite source model is applied to generate three-component rock motions at three bridge sites within the New Madrid Seismic Zone for various combinations of fault mechanism, moment magnitude, and distance. To take into account the uncertainties associated with the earthquake rupturing process, an equal-weight logic tree of all parameters in the composite source model is developed so that every parameter is within physical, geological, and seismological constraints. The results are validated by comparing the average of peak rock accelerations of the 100 simulations of each combination with those derived from an attenuation relation that is representative to the Central and Eastern United States. The characteristics of near-field motions are also examined.