An analysis has been made to determine the reduction in stagnation point heat transfer when blowing and a magnetic field act simultaneously. It is found that in the presence of blowing, the magnetic field may be considerably more effective in reducing heat transfer than in the no-blowing case. The results show that the heat transfer reduction due to the simultaneous action of blowing and magnetic field is greater than that attained by multiplying together the separate reductions due to blowing alone and magnetic field alone. This favourable interaction diminishes as the Prandtl number diminishes and thus may be of lesser importance for highly ionized gases for which the Prandtl number is low. The analysis is carried through for both two- and three-dimensional stagnation points, and results are reported for Prandtl numbers of 0.01, 0.1, 0.7, 1, and 10.