Abstract T hin, one-dimensional shock pulses were generated in a nonlinear viscoelastic material (polymethyl methacrylate) by a new experimental technique. The observed pulse attenuation was compared with an approximate theory based on the viscoelastic shock amplitude equation. The central assumption of this approximate theory is that the unloading wave propagates as a simple wave. Given an initial pulse shape it is shown that the attenuation and the pulse shape at any later time are accurately approximated. The calculated attenuation in polymethyl methacrylate agreed well with the experimental results.