A two-disc machine was used to study crack propagation rate in polymethylmethacrylate (PMMA) subjected to cyclic loading created by a rolling contact. An initial crack of known length was created in PMMA disc, and its growth under known load conditions continuously monitored. It appears that after initial rapid crack growth there is a period of noticeable reduction in the crack growth rate. A rate equation based on the Paris approach is derived and its coefficients found to be m(p) = 0.705 and C-p = 2.93 x 10(-4).