A comparative study of simple and polymer liquid spreading was carried out using isothermal molecular dynamics. In both cases, droplets were composed of 3000 atoms or interacting centers of chain-like molecules. To investigate the spreading mechanism, the labeled atom technique was used. It was found that a single mechanism is not adequate to the simple nanodroplet spreading. Polymer droplet spreading involved a special mode of chains reptation, i.e. their slippage along the substrate. Kinetic curves for the first (lower) monolayer radius r 1 , i.e. dependences of r 1 versus time, are analyzed for the cases of simple and polymer nanodroplet spreading.