We show that the double-peaked emission lines observed in the active g
alaxy 3C 390.3 cannot be produced by two line-emitting streams (genera
ted by a two-sided jet). The reason for this is that, as we show, the
emitting region on the receding jet is obscured from view by the accre
tion disk, leaving the accretion disk as the only viable site for the
production of these lines.