The single bremsstrahlung is studied here with Bloch and Nordsieck’s approximation. The resulting formula is compared with that obtained by the perturbation method. The agreement of the two formulae for low energy photons is verified. Then we study the polarization of the emitted radiation, using our approximate formula. In particular we show in a simple way that, for emission angles lying in a certain range of values, the emitted radiation is mostly polarized with its electric vector perpendicular to the emission plane, in agreement with Wick’s results. Moreover it appears that, for a certain angle of emission, the low energy photons are entirely polarized with the electric vector perpendicular to the emission plane.