The 33-year-old Finland international keeper has put pen to paper on a new two-year deal at The Cottage.
"Antti is an integral part of this Fulham team and his loss last season because of the neck injury was, I understand, a testing time for the team," manager Lawrie Sanchez told the club's official website.
"I'm glad that he is in good health and is committed to us for the next two seasons."