Abstract: For a class of nonlinear systems with iISS unmodeled dynamics, this paper investigates the problem of state-feedback regulation. Using the backstepping technique and the properties of iISS, by appropriately choosing the designed functions and update laws of parameters, we give the design procedure of a state-feedback controller. The designed controller guarantees that all the signals of the closed-loop system are bounded, and that the states can be regulated asymptotically to zero. A simulation example demonstrates the effectiveness of the control scheme.