The 25-year-old, who parted company with Boro earlier this month, signed a short-term deal with the Robins on Friday, which will keep him at Ashton Gate until January.
The defender has been plagued by injuries in recent years and is now glad to be in new surroundings as he looks to get his career back on track.
"Boro are my hometown club, they're the team I supported as a boy and I made my professional debut there," Bates told Bristol City's official website. "I captained the team and made over 100 appearances for the club - of course it was hard to leave, but I just felt a change of club, a change of manager and a change of surroundings would do me good."
He added: "I was aware it was on the fixture list. I don't like to look or think too far ahead so I concentrated fully on the Blackpool game (on Saturday).
"It will be strange going back there. I've still got plenty of friends there and it will be good to see them. I'll have to see what the gaffer wants to do first. If he wants to pick me then I'll be ready."