Electronic Journal of Differential Equations, Vol. 2014 (2014), No. 54, pp. 1-9. Title: Block-pulse functions and their applications to solving systems of higher-order nonlinear Volterra integro-differential equations Authors: Ali Ebadian (Urmia Univ., Urmia, Iran) Amir Ahmad Khajehnasiri (Urmia Univ., Urmia, Iran) Abstract: The operational block-pulse functions, a well-known method for solving functional equations, is employed to solve a system of nonlinear Volterra integro-differential equations. First, we present the block-pulse operational matrix of integration, then by using these matrices, the nonlinear Volterra high-order integro-differential equation is reduced to an algebraic system. The benefits of this method is low cost of setting up the equations without applying any projection method such as Galerkin, collocation, etc. The results reveal that the method is very effective and convenient. Submitted May 4, 2013. Published February 21, 2014. Math Subject Classifications: 45G10, 45D05. Key Words: Operational matrix; Volterra integral equations; block-pulse function.