Provided is a method of fabricating a multi-chip stack package. The method includes preparing single-bodied lower chips having a single-bodied lower chip substrate having a first surface and a second surface disposed opposite the first surface, bonding unit package substrates onto the first surface of the single-bodied lower chip substrate to form a single-bodied substrate-chip bonding structure, separating the single-bodied substrate-chip bonding structure into a plurality of unit substrate-chip bonding structures, preparing single-bodied upper chips having a single-bodied upper chip substrate, bonding the plurality of unit substrate-chip bonding structures onto a first surface of the single-bodied upper chip substrate to form a single-bodied semiconductor chip stack structure, and separating the single-bodied semiconductor chip stack structure into a plurality of unit semiconductor chip stack structures.