A theoretical and numerical analysis of the propagation of electromagnetic waves in the nightside Venus ionosphere is presented. The special case of propagation parallel to the magnetic field is considered. The model assumes a source of electromagnetic radiation in the Venus atmosphere, such as produced by lightning, and specifically addresses wave propagation for realistic ionosphreic parameters in the altitude range z=130--160 km at the four frequencies detectable by the Pioneer Venus Orbiter Electric Field Detector (OEFD): 100 Hz, 730 Hz, 5.4 kHz, and 30 kHz. The results are summarized as follows. The f=100 Hz and 730 Hz waves can propagate as whistler waves, provided ff>fce.