Stress-strain data for nylon and dacron webbing of 5500 and 6000 pound strengths are presented for quasi-static and very rapid loading rates up to about 450,000 pounds per second. The preliminary data indicates that the stress-strain slope is about twice as great with both materials for the rapid loading rates. The results also indicate that the failure load is the slightly higher (6 to 18 percent) for the rapid loading. The variation of the stress-strain slope with a changed loading rate will undoubtedly have an effect on the prediction of loads and accelerations for crash restraint systems in all types of vehicles.