The French international struggled with injuries throughout last season and was linked with a move away from the club at one stage.
He has begun a full pre-season programme this season, and is concentrating on doing well for the Gunners.
"I'm very happy," Sagna told the club's official website.
"Last year I missed pre-season so I was struggling a bit during the season.
"I'm looking forward to getting back to my best, that's my aim and after that we'll see."
Sagna was part of the Arsenal side which beat an Indonesian XI 7-0 yesterday.