The stability problem for functional equations have been extensively investigated by a number of mathematicians. During the last five decades, a number of research papers and research monographs have been published on various generalizations and applications of the Hyers-Ulam stability for several functional equations, and there are interesting results related to this problem. In this research article, we investigate the generalized Hyers-Ulam stability of the functional equation f(2x+y)+f(x+2y) = 4f(x+y)+f(x)+f(y) in 2-Banach space, where f : X −→ X.