An orthopedic casting tape providing stretchability which comprises a knitted fibrous substrate impregnated with a water-curable synthetic resin wherein the substrate consists of synthetic organic fiber stretch yarn solely, in part stretch yarn and in part natural fibers, in part stretch yarn and in part artificial fibers or in part stretch yarn and in part mixtures of natural and artificial fibers. The stretch yarns are preferably those in which the stretchability is conferred by providing spiral or zigzag patterns of the synthetic fibers and utilizing the thermal plasticity and shrinkage properties of the synthetic fibers which are non-elastomeric.
