This study deal with functional integral and integro-differential equations of the Fredholm-Volterra type in linear form subject to initial conditions based on Dejdumrong polynomial operational matrix is derived. This kind of problems are used in many fields of engineering, science, electronics, biological, physics and, mechanics. By using the suggest method the problem convert to system of linear algebraic equations. By solving this system yields Dejdumrong polynomial unknown coefficients of the approximate solution. The absolute error are drive and improve by using the residual error function. Two test problem are include to demonstrate the applicability and validity of using Dejdumrong polynomial matrix collocation method.