This paper is the second of two papers which present the results of an experimental study to verify the use of a single bottom roughness length scale to characterize wave and current boundary layer flows over a rough bed. While the first paper <Mathisen and Madsen, this issue> included analysis of wave attenuation measurements to estimate the bottom roughness experienced by waves in the presence and absence of a current, this paper includes the analysis of time-averaged velocity profiles to estimate the bottom and apparent roughness experienced by a current in the presence of waves. In this paper, velocity profiles predicted by the Grant and Madsen <1986> model are compared with measured velocity profiles. Apparent hydraulic roughness predictions of the Grant and Madsen <1986> model are shown to underpredict the apparent hydraulic roughnesses experienced by the current. This difference is shown to be a result of an underprediction of the wave boundary layer thickness and of a steady streaming or mass transport which is induced by the wave motion within the wave boundary layer of the combined wave-current flow. By modifying the wave boundary layer thickness and estimating the wave-induced mass transport from pure wave experiments, the bottom roughness for pure current, pure wave, and combined wave-current boundary layer flows is shown to be characterized by a single roughness scale. ¿ American Geophysical Union 1996