Spatial aliasing of Kirchhoff migration imaging operators can seriously degrade the quality of subsurface reflectivity images. Sparse and/or irregular 3-D acquisition geometries can adversely magnify the problem in the presence of steep reflector dip. An anti-aliasing method is implemented to ameliorate Kirchhoff migration operator aliasing, based on local time and dip variant triangle filtering. The local anti-aliasing filters are efficiently applied as 3-point time filters after a step each of causal and acausal temporal trace integration. The anti-aliased migration is compared to a standard aperture-weighted Kirchhoff 3-D poststack time migration of a steep-dip salt intrusion from the Gulf of Mexico. Preliminary results indicate that the anti-aliased migration appears to enhance the resolution of steep salt-sediment interfaces and faults, compared to the standard migration. Both algorithms are implemented on the 32-node Connection Machine (CM5) at the Stanford Exploration Project.