Boothroyd has enjoyed a successful first year with Watford

Boothroyd had been on a rolling one-year deal but has been rewarded after guiding the Hornets to third in the Coca-Cola Championship.

Chairman Graham Simpson said: "Adrian combines exceptional man-management skills with the very best in pure football coaching qualities."

Boothroyd had been linked with the managerial vacancy at Southampton.

Boothroyd told the club's website: "In a very short space of time Watford has come to mean an awful lot to me.

"I am conscious, however, that we have won nothing yet but I am confident that success will be achieved.

I am confident we now have a platform in place that enables us to mount a serious challenge Graham Simpson

"Winning a place in the Premier League is quite clearly the over-riding priority for me - and I am committed to delivering this, sooner rather than later."

Simpson said: "In a short space of time, he has taken this club by the scruff of the neck and given us new purpose, vigour and far greater self belief.

"We are delighted that he has committed to the Watford cause until 2010.

"With Adrian at the helm, I am confident we now have a platform in place that enables us to mount a serious challenge at English football's highest level."