We consider a linear model reference control system in which the plant system and input matrices are uncertain and the plant state and control have retarded arguments. We present a control system consisting of a non-linear control law to handle the uncertainties. Under certain assumptions, this controller guarantees that all solutions are uniformly ultimately bounded. We also demonstrate the attractiveness of the switching hypersurface and show that along the hypersurface the trajectories are insensitive to system parameter variations.