The contact interaction between a rough cylindrical body (i.e., with asperities) and a deformable smooth flat was investigated using the finite-element analysis. Analysis included both elastic–plastic deformation and friction. Further, the effects of several parameters of rough surface on the evolution of the contact area with increasing contact load were investigated. These were radius, number, constraint, and placement of asperities. Contact area of rough surface is smaller than its counterpart of smooth surface, and this decrease depends on number, radius, constraint, and placement of asperities. The elastic material behavior results in considerably smaller contact area than that from elastic–plastic material behavior. The evolution of contact area with increasing contact load is of the complex nature with elastic–plastic material deformation since the yielded region widens and/or deepens with increasing load depending on number, radius, and constraint of asperities. The effect of constraint on the asperity depends upon its nature (i.e., from either sides or one side) and radius of the asperity. The effects of these several parameters on the contact area versus applied load relationships are expressed in the graphical form as well as in terms of equations wherever possible.