Non-equilibrium molecular dynamics is used to study the indentation of an ideal metallic surface by a hard spherical ball. The problem is symmetric about the axis of the ball and we choose to study the deformation in two dimensions. We use the simple embedding function F(ρ) = 2eρln ρ along with the Lennard-Jones two body potential to model a material resembling copper. We present a calculation of the st'ress field (from the internal atomistic description) for both elastic and plastic deformations. The material deforms plastically through the creation of edge dislocations and the flow of material around the sides of the indenter. The creation of dislocations is reversible—they return to the surface (anneal out) when the indenter is removed. The plastic flow leads to a permanent indentation in the surface.