Abstract: A remailable envelope is constructed of a single sheet folded in half having perforations spaced inward from the non-folded edges. A flap fold is spaced inward parallel to the perforation at the free edge of the back. Adhesive extends between the centerfold and the flap fold on the inner surface of the detachable lateral portions between the perforations and the lateral edges. Adhesive strips with release sheets are attached to the outer back face inside the perforations. Adhesive strips with release sheets are attached to an inside of the flap on the detachable portion between the perforation and the terminal edge. Adhesive strips with release covers are applied to the outer face of the flap inside the perforations. The envelope is preaddressed on the outer front face and may be preaddressed and stamped as a return envelope on the inner front face. In use the flap is folded down and material is placed inside the envelope.