Abstract: A method for producing a sealed rope of braided or twisted filaments. Heat-shrinkable filaments are braided or twisted about a core of a thermoplastic material to form a rope and the rope is placed under tension and treated to cause the thermoplastic core material to melt. Simultaneously the rope is maintained at a temperature sufficient to cause the heat-shrinkable filaments to shrink but not to melt, whereby the shrinking of the filaments, while the rope is under tension, reduces the cross section of the rope and causes the material to penetrate into the openings between and to surround and seal the filaments of the rope.