In this note we consider the problem of feedback control of n-dof (degree-of-freedom) rigid manipulators subject to a scalar unilateral constraint f(X) 0 (X ∈ Rn is the vector of generalized coordinates). The stability analysis relies on a stability concept that incorporates the hybrid dynamical feature of the overall system. It is shown that stability of the closed-loop system can be obtained. It is pointed out that showing asymptotic stability certainly requires more advanced stability tools.