In this paper, optimization problems P with complementarity constraints are considered. Characterizations for local minimizers &xmacr; of P of Orders 1 and 2 are presented. We analyze a parametric smoothing approach for solving these programs in which P is replaced by a perturbed problem P
τ depending on a (small) parameter τ. We are interested in the convergence behavior of the feasible set ℱτ and the convergence of the solutions &xmacr;τ of P
τ for τ→ 0. In particular, it is shown that, under generic assumptions, the solutions &xmacr;τare unique and converge to a solution &xmacr;of P with a rate 𝒪(√τ). Moreover, the convergence for the Hausdorff distance d(ℱτ, ℱ) between the feasible sets of P
τ and P is of order 𝒪(√τ).
