The experienced duo have confirmed they will be exiting San Siro at the end of the season after more than a decade of service at the Serie A giants
Both players have expiring contracts with Milan and have been allowed by the Rossoneri to leave after a season in which they featured infrequently.
The duo are the second and third Milan veterans to wave goodbye to the club in the space of days, after Alessandro Nesta revealed on Thursday that he will quit San Siro in the summer.
Gattuso, who joined Milan from Salernitana in 1999, has made only six appearances this season after a serious eye problem forced him to spend several months on the sidelines.
He said earlier in the week that he could retire from football if he was not guaranteed an active role at Milan next season, but he has now opened the door to a challenge.
"I leave because the time has come for me to give room to other players," he told reporters.
"I will explain everything at a press conference on Saturday. I do not know yet where I will go, I have not yet decided."
Inzaghi, 38, has been at Milan since 2001, when he joined the club from Juventus in a 37 million euro deal, scoring 125 goals in 296 appearances for the Rossoneri.
He has only made eight appearances to date in 2011-12, with his brother, Simone, revealing that the Milan ace will not retire from football just yet.
"Today I would like to thank with affection and emotion President Berlusconi and Adriano Galliani," Inzaghi said in a open letter, published on Milan's website.
"Their electricity and their ability to transmit emotion for me made me stronger and pushed me beyond any and all limits.
"But I also want to give a thought to those who, from the youth sector to all the wonderful clubs that I’ve played for, helped me to become the man and the player that I am today.
"Thank you Milan, thank you football. Allow me to call you my own, the people of Via Turati, from Milanello to the offices to the phone operators to the warehouse workers, the physiotherapists, the doctors, the cooks, from the stadium to the changing room.
"Ciao Carlo Ancelotti, I won a lot with you, ciao to my wonderful fans who followed me the world over with affection and passion. Ciao to my teammates from today and yesterday."
More players could join the Milan exodus in the next few days, as seven other footballers have expiring contracts with the Rossoneri.