The midfielder has agreed to join Ian Baraclough's side for the 2014 season, while Raffaele Cretaro has re-signed for another year at the Showgrounds
O'Conor moved to Hunky Dorys Park at the start of the 2013 season from UCD, and scored the opening goal for Drogs in the FAI Cup Final, but saw Sligo come from behind to lift the trophy. 32-year-old Cretaro is a fan favourite at the Showgrounds, having made 393 appearances for Rovers.
Bit o' Red manager Ian Baraclough expressed his delight at signing the duo for the 2014 campaign. "In Paul I feel we have signed one of the outstanding midfield players in the country," Baraclough told the club's official website.
"He is accomplished on the ball, he scores goals and he can flourish in the horrible side of the game. You see his progression with Drogheda and I feel this is the right move for him now. He is the right age at 26. He has all the attributes to be a huge player for us in 2014.
"With Raff, you look at a number of things. Consistency, passion, giving 100% to the cause. He is a hero to the Sligo Rovers fans and that is because of all of the above. He still has personal goals. There is a powerful drive to possibly make the most appearances in the history of the club. It tells you all you need to know.
"He is a player I’m delighted to have part of the squad, a character that you always want with you. This is the first of many signings we will be making in next period. There is a feel good factor in what we are doing and as the club launches season tickets for next season, I can promise you in 2014 our ambitions are as high as ever."