Abstract: A composite interlining sheet material for garments and the like is disclosed. The composite interlining sheet material comprises a substantially continuous internal layer of porous material having low heat conductivity and high resilience. The internal layer is of a substantially uniform thickness and consistency, and its composition and thickness is such that it is supple and drapable. A continuous layer of flexible reflective material is bonded to the outside of the internal layer at at least spaced intervals and functions to reduce the conduction of heat away from the internal layer and decrease the emissivity of the composite sheet, the outside being the side which is to be disposed away from the body of the wearer or person when used as a interlining of a garment or the like when it is desired to maximize heat retention.