The spreading of Newtonian liquid drops after impact with a solid surface is reproted for a range of liquid and surface proeprties, drop diameters, and impact velocities. Results for liquid viscosities up to 300 mPa.s are given. For a given drop diameter and velocity, a range of liquid viscosities result in splashing even for smooth surfaces. The maximum spread radius, made dimensionless with the drop radius, is correlated as Rmax* = 0.61(Re2Oh)0.166, where Re and Oh are the Reynolds and Ohnesorge numbers. respectively. A model is proposed to account for inertial, viscous, and surface tension forces on the maximum spread radius. Good agreement is found between the model and experimental data from several sources.