This paper presents a numerical and experimental study on attenuation of structurally radiated sound from an elastic cylindrical shell by local vibration control. An analytical model is developed for the active structural acoustic control (ASAC) of the cylindrical shell. A local control strategy is considered by minimization of the mean-square velocity of finite discrete locations. Numerical simulations are performed to examine and analyze the control performance. Results show that global sound attenuation of the cylindrical shell can be obtained at resonance frequencies. However, control spillover may occur at off-resonance frequencies. Modal suppression and rearrangement mechanisms may be involved in the control process. ASAC experiment was implemented by FXLMS algorithm, good agreement was observed between the numerical and experimental results, and successful attenuation of radiated sound was achieved.