Simulations of flow and heat transfer in complex geometries with flow-structure-interaction (FSI) require special treatment. In this paper, an approach that combines the immersed boundary method (IBM) for handling complex moving boundaries and the material point method (MPM) for resolving structural stresses and movement is presented as an approach for solving FSI problems. In the IBM, a Cartesian grid is generally defined, and the variable values at grid points adjacent to a non-Cartesian boundary are forced or interpolated to satisfy the boundary conditions. MPM is used to solve equations of solid structure (stresses and deflection) and communicates with the fluid through appropriate interfaceboundary conditions. Several examples of using this combination of IBM&MPM are presented and the advantages and disadvantages of this approach are outlined.