Wave setup and swash statistics were calculated from 154 runup time series measured on a moderately steep beach under incident waves varying from 0.4 to 4.0 m significant wave height. When scaled by the incident wave height, setup, swash height, and total runup (the sum of setup and half the swash height) were found to vary linearly with the surf zone similarity parameter &xgr;0=β(H0/L0)-1/2. The foreshore slope appeared the appropriate value for the calculation of &xgr;0, although the setup data showed some influence of an offshore bar at low tide. For low Irribaren numbers the swash height in the incident frequency band becomes saturated, while for high Irribaren numbers, no such signs of saturations were seen. Thus the infragravity band appears to become dominant in the swash below some value of &xgr;0. For these data, that value is approximately 1.75, although there is considerable scatter associated with that estimate.