This paper presents a large eddy simulation (LES) of flow and heat transfer in a tandem configuration of two square cylinders at moderate Reynolds number (). Compressible LES on a hybrid mesh is used to predict the flow structure and the heat transfer at the wall. The goals of this work are to analyze the flow and the heat transfer around a tandem arrangement of two inline square cylinders as well as to propose a LES approach that can be applied to convective heat transfer problems in industrial configurations. The meshing strategy allows to resolve the flow field until the viscous sublayer with y+ of the order unity. The wall adapting linear eddy model is chosen to model the subgrid turbulent viscosity. Aerodynamics results are validated versus experimental measurements performed on isolated cylinders and on tandem configurations. The main flow structures responsible for heat transfer are analyzed. Finally, heat transfer around both cylinders of the tandem is described.