A numerical model able to simulate the Mixed Lubrication regime is developed. It is governed by the Reynolds equation in Elasto-Hydrodynamic mode and the contact equation, where the transition between lubricated and contact areas is managed by a transition function leading to a global set of nonlinear equations. The surfaces’ deformability is evaluated with the Boundary Element Method. The roughness is generated by the Random Mid-Point algorithm which models fractal surfaces. Firstly, the model is applied to a fixed spherical asperity pushed against a moving plane and a sensitivity analysis is conducted. Finally, the model is applied to a fixed rough surface pushed against a moving plane and the results are compared to the Dry Contact case.