A method of fabricating a thermally insulating stretchable down feather sheet is described. The core of the sheet is comprised of down mixed with a binder mixture which exhibits elastic properties. The binder mixture consists of heat fusible stretchable glue particles and heat fusible elastomeric binding strands in dry form. The core is sandwiched between a bottom and a top stretchable elastomeric sheet having multi-directional stretchability. The core of down and the binder as well as the elastomeric sheet are bound together by heat treatment to provide a down insulating sheet which is stretchable in all directions without fractioning the sheet and which is capable of recovering substantially its original relaxed form after stretching or deformation.