The keeper was offered a new deal some time ago, but that had to be filed away when his wife was suddenly taken ill just before Christmas.
But when Van der sar returned, he took his place back between the sticks as soon as he recovered from a slight knee injury.
He has since played in United's last nine matches and is now convinced he can carry on for a further year.
"I would like to keep on playing so I have decided to sign another contract," he said
"The club want me to stay and I'm happy here. My fitness is good and I feel I can carry on playing for United.
"It's been a hard time for all the family and when something like this happens it's a tough situation.''