||Numerical investigation of the two-dimensional flow and heat transfer, in a horizontal channel differentially heated and obstructed by an inclined square cylinder mounted to the approaching flow with an angle of inclination equal to 45° is carried out. The strategy is based on the combination of the Multiple Relaxation Time Lattice Boltzmann Equation (MRT-LBE) to obtain the velocities and on the Finite Differences Method (FDM) to solve the equation of energy. This numerical scheme is assessed against previous publications. Close attention is paid to Reynolds number ranging from 0 to 300 at Prandtl number, Pr = 0.71 with constant physical properties of the fluid. Results are presented in terms of streamline contours, isotherms, drag coefficient, Strouhal number, local and average Nusselt numbers for various Reynolds numbers. The computed results show that the presence of such bluff body affects significantly the fluid flow and causes enhancement in the heat transfer from the hot bottom wall to the flow.