In this paper, we have established two general integral formulas involving Humbert hypergeometric functions of two variables $\Phi_{2}$ and $\Psi_{2}$. The results are obtained with the help of a generalization of classical Kummer's summation theorem on the sum of the series ${}_{2}F_{1}(-1)$ due to Lavoie et al. [5]. Some interesting applications are also presented.