Struggling Doncaster kept their second clean sheet of the season to earn a point against Watford.
Home sub Kyle Bennett came closest to breaking the deadlock after coming on but his fierce shot flew just wide.
On-loan winger Michael Kightly had the visitors' best chance but his dipping volley hit the woodwork.
Hornets striker Marvin Sordell went off injured and his side have now failed to find the back of the net in nine league games this season.
Doncaster stay bottom despite the draw.