Fidler is a vastly experienced player and made over 250 appearances in a successful career spanning nine years for the 'Cherry and Whites' as he followed in the footsteps of his father John, who also played for England and Gloucester.
The 28-year-old won two caps for England on the infamous tour of the southern hemisphere in 1998 and was looking forward to the new challenge.
"Having seen the players that Bath Rugby have added to their existing squad I am pleased to have signed for them and I am looking forward to next season as a fresh challenge in my career and to help Bath Rugby re-establish themselves at the top end of the Zurich Premiership," said Fidler.
Certainly, Bath's director of rugby Jack Rowell believes that Fidler will add much-needed firepower and experience to the Bath Rugby second row with Danny Grewcock and Steve Borthwick in line for possible World Cup call-ups.
"Rob is a vastly experienced and extremely competitive lock forward," said Rowell.
"He has achieved success with Gloucester over the past nine years and thereby provides much-needed depth and experience within the Bath Rugby first team squad where international calls for Grewcock and Borthwick have taken their toll.
"Rob himself, in addition to his substantial experience in the Zurich Premiership has represented England and at 28, joins Bath Rugby with a view to continuing his ambitions and appetite for first-class rugby."
Fidler will meet up with his new team-mates for pre-season training in July.