The WUMa contact binary VW Cep has a period of 0.2783 days, spectral type G5+K1 and mass 1.1+0.4. Mʘ. Our three-colour photoelectric measurements made in Sept. and Oct. 1964 confirmed the existence of the Kwee effect in this system. We believe that if the Kwee effect is to be explained in terms of moving gas streams the influence of magnetic fields must be considered. It is assumed that there is a deep convection zone on the primary accompanied by a dipole magnetic field. This field is distorted by the moving gas streams to form a ring-like configuration with an enhanced field strength close to the inner Lagrangian point, L1 (see figure l), where large groups of spots form. We suppose the magnetic field in the spots to be 5000G and the general field to be ~10–20 G.