Abstract: An electronic device such as a portable computer is shielded against electromagnetic interference using a flexible envelope that surrounds a circuit card within the housing of the device. The flexible envelope forms a shielding enclosure and has an electrically insulating flexible sheet, for example of polyethylene, and a sheet of conductive fibers embedded in the flexible sheet so as to leave a nonconductive face oriented toward the circuit card. The conductive fibers can be metallized nylon and are sufficiently dense to obtain a resistivity of 10.sup.-1 to 10.sup.-2 .OMEGA./.quadrature.. The enclosure forms a hollow envelope with the conductive fibers coupled electrically across a seam, for example by cutting the flexible sheet and embedded fibers using heat. For use with a portable computer having a pivoting screen, a neck extension of the enclosure carries conductors through the area of the pivot.