Pena had played in Mexican Liga MX for Leon and Chivas Guadalajara before making his move to the ranks of Scottish side.
Carlos Pena has completed his move from Rangers to Cruz Azul, where he will join up once again with former Ibrox boss Pedro Caixinha.
"The 27-year-old departs until next January having netted five goals in 14 games for the Light Blues".
Jordan Thompson has departed on loan to Livingston until the end of the season, but Rangers have been linked with a move for former Hibernian striker Jason Cummings, who is now at Nottingham Forest.
"This is a new stage, I hope to be very good and give a lot of joy to this club and give them many triumphs", Pena told a press conference as he was presented.
He has 19 caps and two goals for Mexico to his name.
Following Caixinha's sacking from the Ibrox post and appointment at Cruz Azul, the Portuguese boss made re-signing Pena one of his top priorities.
"I've come here with maturity and with the idea to [taste] success".
Meanwhile, Rangers have confirmed former players Kevin Thomson and Gregory Vignal have rejoined the club to work in Gers' academy set-up.