Talismanic skipper Sanderson - known as Captain Fantastic to his army of fans - joined Worcester Warriors for the start of the 2004/05 season and has been instrumental in ensuring the club has retained top-flight status.
The 31-year-old started every top-flight game in his first year with the club and was later nominated for the Zurich Player of the Season and the PRA Players' Player of the Year.
An incredibly fit, intelligent, skilful and hard-working back row, Sanderson has always led from the front at Sixways, both on and off the field, and has now played 115 games for the club and scored 110 points.
Director of Rugby Mike Ruddock is delighted that his captain had chosen to commit to the club a year early, with his current deal set to run until the end of the 2009/10 campaign.
"It is fantastic news that Pat Sanderson has decided to extend his term at Warriors," said Ruddock. "Pat has always been the consummate professional, an outstanding performer, great player and top leader during his time at the club.
