Both players have been linked with summer departures from the Santiago Bernabeu after falling down the pecking order in Jose Mourinho's squad.
Kaka has failed to make a significant impact in his three years in La Liga and is expected to leave should Madrid sign Luka Modric from Tottenham Hotspur.
Turkey international Sahin was a fringe player for Los Blancos in 2011-12 following his arrival from Borussia Dortmund last summer.
Galatasaray have now stated that they are interested to sign both players, especially Kaka.
"Kaka and Sahin are both set to leave," club president Unal Aysa told Calciomercato.com. "We definitely want the Brazilian.
"We will only know his final destination when the transfer is complete."
Kaka has been heavily linked with a move back to AC Milan, while Sahin is reportedly on the radar of English clubs Arsenal and Liverpool.