A model of the 'full up' nightside ionosphere of Venus is presented for the equatorial midnight region. We propose keV electron impact as the strongest source of ionization leading to peak ion density of ?105 cm-3 which was observed by the PV-OIMS experiment on several occasions. The observed altitude profiles of CO2+, O+, O2+, H+ and H2+ (or D+) can be reproduced with this model if available keV electron flux is approximated by ϕ (E)~100 E e-E/1000 in 0.3-3.0 keV range. This is a reasonable extrapolation of fluxes observed at lower energies.