The use of active vibration control techniques applying piezoelectric actuators can show satisfactory results. This paper proposes an active vibration control technique based on H-infinity Norm, which is applied to a piezoelectric actuator bonded to a composite structure forming a so-called smart composite structure. The structural model is stablished for a rectangular shape beam by Serendipity type finite element based on first-order shear deformation theory with eight nodes, five degrees of freedom (DOF) per node and eight electrical DOF per piezoelectric. Furthermore, a mixed theory that uses a single equivalent layer for the discretization of the mechanical displacement field and a layerwise representation of the electrical field is adopted. Temperature effects are neglected. Simulation results show the effectiveness of the proposed control methodology for composite structures.