In this article, we are utilizing variation of parameters method in integro differential equations. These equations assume a dynamic job in demonstrating of numerous physical developments in science and engineering. Motivated and inspired by these facts, we are applying sucessfully analytic technique to solve first-order Fredholm Integro Differential Equations (FIDE) and Voltera Integro Differential Equation (VIDE). The recommended technique is applied with no discretization, linearization, Perturbation, transformation, preventive presumptions and is liberated from Adomian's polynomials. Various models are given to determine the legitimacy and appropriateness of the proposed technique.