Abstract: A negotiable instrument mailing device is formed from a single, generally continuous blank of paper or the like. The blank includes an addressee panel, a return address panel and a negotiable instrument panel. The negotiable instrument panel is imprinted with normal negotiable instrument indicia. The addressee panel is imprinted with the address of the addressee and includes a window opening. The return address panel is imprinted with the return address at a location so that when the return address panel is folded relative to the addressee panel, the return address is in registry with the window opening. Adhesive means are provided for securing the return address panel to the addressee panel when folded to form a generally sealed return envelope.