Captain Toulalan has put pen to paper on a new two-year deal to keep him under contract with the club until 2017 while goalkeeper Subasic is tied down until 2019.
Moroccan midfielder Nabil Dirar and defender Andrea Raggi agreed terms until 2018.
Toulalan, 31, has been linked with a move to Inter in recent weeks but the experienced Frenchman is eager to help maintain Monaco's domestic and continental progress.
"I came here to go as high as possible. This was done in the first year by reaching the Champions League," he told the club's official website.
"This season we have played well, since we are in the quarter-finals. This is a great adventure and we need to continue. I'll try to help the young players and be as effective as possible."
Subasic added: "I am proud. I have been at AS Monaco since the beginning of this new project and I have played more than 120 matches.
"As the club has grown, I have grown as a player but I want to do more."
