O'Leary has signed up for his 16th season with Swansea

O'Leary, 29, had been offered a three-year deal to join Cheltenham, where he played on loan last season.

Swansea's deal has an offer for another year if the midfielder plays 25 competitive first team games next term.

"Swansea is where my heart is and I hope my decision to turn down the three-year deal proves my commitment to the club," said O'Leary.

Interview: Kristian O'Leary

"I've virtually grown up in a Swansea shirt and I still want to do well for them.

"I know I've got another massive challenge ahead of me with the squad the manager [Roberto Martinez] is putting together; but it's nothing new to me - I've always had challenges."

After finding opportunities limited under previous manager Kenny Jackett last season on his return from injury, O'Leary impressed during a month's loan spell at Cheltenham.

He gradually forced his way back into the Swansea side on his return in December, and ended the season by starting in the last seven games.

"The gaffer played a major part in my decision to stay," he added. "I played with him for a number of years and we built up a strong friendship.

"As a manager, he has brought with him a freshness and plenty of new ideas and now I'm desperate to do well playing under him."

O'Leary is the longest-serving player in the Swansea squad, having been with the club since 1995.

He has made over 300 appearances for the Swans under 14 different managers.