The 31-year-old joined the Magpies in 2008 from Deportivo and has gone on to make over 150 appearances for the club.
He told reporters: "I thought about walking out, but I changed my mind.
"It wasn't about the money. There were personal reasons but the club and manager have been great.
"I've been away from home for 13 years and I miss it. Now is about Newcastle United staying up... and we will."
Coloccini has played 22 times for Alan Pardew's side this season.