On the positive real number, we obtain the Hyers-Ulam stability and a stability in the sense of R. Ger for the generalized beta function g(x+p,y+q) = ${varphi}(x,y)g(x,y)$ in the following settings: $$mid$g(x+p,y+q)-{varphi}(x,y)g(x,y)$mid${leq}{delta}$</TEX> and $$mid$frac{g(x+p,y+q)}{varphi(x,y)g(x,y)}-1$mid${leq}{psi}(x,y). As a consequence we obtain stability theorems for the gamma functional equation and the beta functional equation.