An experimental and theoretical study is,presented on spreading and retracting of a single drop impacting on a smooth surface at room temperature. The experimental study showed the influence of kinetic energy, liquid-solid interaction, and energy dissipation on the impact process. The results are reported for Reynolds number from 180 to 5,513, Weber number from 0.2 to 176, four different liquids (distilled water, n-Octane, n-Tetradecane, and I n-Hexadecane), and four different. surfaces (slide glass, uncoated silicon wafer, HMDS coated silicon wafer, and Teflon fifty). A theoretical model based on an energy balance, was developed to predict the maximum spreading ratio at low impact velocity. The key novel feature of this model is that the shape of the drop is assumed to be a spherical cap during the spreading process. When compared to models in the literature, the present model not only gives better predictions for low drop impact velocities, but also in most cases gives predictions that are within 10% of the experimental data at high impact velocities.