Methods for the completion of subterranean well bores in a multilateral well system are provided. More particularly, methods are provided for the sealing of junctions between lateral well bores and a parent well bore. The sealants used in accordance with the methods provided generally comprise any sealing composition which can be placed within a subterranean formation, and injected a sufficient distance into a region of the formation surrounding a junction between a first well bore and a second well bore in fluid communication with the first well bore, so as to prevent the undesired entry of formation fluids into either well bore in the region surrounding the junction.