The Ecuador striker has been brought in to augment a title-chasing Inter forward line that includes Lautaro Martinez and Edin Dzeko.
Caicedo joined Genoa from Lazio at the start of the season, scoring one goal in 10 appearances, but will now spend the rest of the season with the league leaders.
The 33-year-old’s switch to the San Siro sees him reunite with Inter manager Simone Inzaghi, whom he worked with at Lazio.
"I'm very excited. I want to be a success here," Caicedo, who will wear the number 88 shirt, told Inter's official website.
"I want to thank the coach, Inzaghi, for trying his best to bring me here. I'm delighted and can't wait to start training and playing for Inter.
"I'm really proud to represent my country and to be the first Ecuadorian to play for Inter. I'm very happy and I think I can do very well here."
The former Manchester City striker added on Inzaghi: "I worked with him for four years at Lazio, and now we get to link up again."
"He was really important. He convinced me to join straight away. So I am grateful and can't wait to start training under him again."
Caicedo is Inter’s second winter signing after Atalanta’s Robin Gosens.