A modular foundation design for supporting a wind turbine or telecommunication tower, comprised of pre-cast concrete modules offering advantages of off-site manufacture and ease of transportation, but which deign is simple to construct. A base slab is provided comprised of sub-modules/base members arranged together in juxtaposed position which together provide a horizontal surface on which pre-cast pipe members may be stacked in end-to-end position to form a pedestal. Anchor rods extend through the pipe members into screw retainers in the base members, which rods serve to not only post-tension the pipe members and secure them together, but further advantageously serve to retain the base members together thereby assisting in distributing forces and loads applied to one sub-module/base member over the entire base slab. Coupling means to further couple the base members together may be added to better retain the base members together and still further improve distribution of forces.