The excitation of ion-cyclotron oscillations in a weakly ionized plasma placed in an external d.c. electric field parallel to the field of magnetization is considered and the threshold electron drift is determined. The process is treated kinetically, and elastic collisions of charged particles with neutrals are described by Boltzmann collision integral. It is shown that the oscillations begin in the long-wave region and that their excitation may depend on ion collisions. In moderate magnetic fields (νe ≫ Ωi ≫ νi) electron collisions significantly facilitate the process of excitation.