The ill-posed Cauchy problem on the negative half-line is considered for a nonlinear non-autonomous system of retarded differential equations. The Tikhonov’s regularization method is used for solving it. We choose a special stabilizing functional which is used in the absence of a priori information about smoothness of solutions of the retarded system. We obtain a singular boundary value problem, and the solution of which could be defined as regularized solution of the retarded system on the finite interval of the negative half-plain.