Abstract An intermediate coupling calculation of the drift mobility of polarons has been carried out, using Kubo's formula for the linear response coëfficient, together with a modified L.L.P. polaron model. At low temperatures the drift mobility turns out to be μ = e m ∗ 2αω ν(1 + 0.06α) where α is the electron-phonon coupling constant and m ∗ the effective mass of the polaron, given by m ∗ = m (i + α 6 ) (1 + 0.2 α ν) . A comparison, made with other intermediate coupling theories, shows that the obtained mobility expression agrees closely with Osaka's formula in the coupling range α ⩽ 3. The calculation correction term being μ 0.06 α (1 + 0.06 α) , justifies the validity of the obtained results in the intermediate coupling range.