The influential midfielder has extended his current deal by a further 12 months.
Legwinski told the club's website, www.fulhamfc.com: "I'm happy to stay at Fulham, as I have always maintained, and I'm happy to think about ending my career here.
"I am really enjoying my time at the club, my team-mates are great and the atmosphere inside the club is very good.
"The challenge from when I first signed is still the same and is very interesting.
"We all came with the objective to build a strong squad here at Fulham and for me this is a challenge that I want to fight for and I believe that the club is heading in the right direction."