This paper investigates the problem of semiglobal L2 disturbance attenuation for a class of nonlinear systems. By [4], our purpose of designing controllers is just to attenuate all disturbances in a given bounded subset of L2 [0, ∞]. We prove that for any such a given bounded subset there exist partial state feedbacks and dynamic output feedbacks respectively which attenuate each disturbance in the given bounded subset in the L2 gain sense and attain asymptotic stability without disturbance.