The 34-year-old Brazil international has committed his future to Vicarage Road until 2018 after helping the Hornets achieve promotion to the Premier League.
Gomes, who made more than 100 top-flight appearances for previous club Tottenham, kept 15 clean sheets during 44 matches last term and was second to striker Troy Deeney in Watford’s Player of the Year vote.
He told the Hornets’ website: “I am familiar with the club and everyone here. Some people were not sure what I was going to do here but when you have the respect of the people and the fans it’s great.
“That’s why I want to stay here for a long time. When you feel good you want to continue and I feel good.”