The announcement came after the transfer window had closed for the Premier League, but the strugglers managed to get the paperwork delivered in time to seal the deal.
N'Doye's arrival will be a welcome relief to Hull manager Steve Bruce, who has been desperate to boost his striking options during the transfer window.
Hull are languishing in the Premier League relegation zone and have managed just 20 goals this season - only Aston Villa have registered fewer this term.
Senegal international N'Doye has scored four goals in nine starts for Russian Premier League side Lokomotiv this season and could make his debut at champions Manchester City on Saturday.
N'Doye recently represented his country at the Africa Cup of Nations but Senegal were eliminated at the group stage.
