Mean neutral wind velocity vectors observed at auroral E region altitudes by European incoherent scatter radar (EISCAT) for disturbed days are found to be rather similar to the mean wind velocity vectors observed on quiet days. It is demonstrated that the main difference in the E field between quiet and disturbed days is an enhancement in the diurnal component by a factor of 3. The semidiurnal, 6-, and 8-hour components display only minor differences. The amplitudes of the tidal components of the neutral wind increase in general above 109 km during ionospheric disturbances in particular for the diurnal tide of the zonal wind. The disturbance pattern of the neutral wind has a stronger equatorward component above ~109 km than the corresponding quiet time pattern. In general, on disturbed days there is an additional eastward motion from the late evening until prenoon. During the daytime the northward wind is enhanced, while in the afternoon stronger westward velocities are seen above 109 km. In the afternoon sector until late evening during disturbed conditions there is also a southward component above ~109 km. Below 109 km the semidiurnal tide appears to be enhanced during disturbed conditions. It is found that only part of the disturbance in the E region neutral wind can be explained by ion drag while Joule heating and particle precipitation may play an additional role. Satisfying agreement is found between the variations of the diurnal components of the E region neutral wind observed in the present work and the recent model predictions by Fesen et al. [1991>. ¿ American Geophysical Union 1995