Zimmer received a three-year contract to stay with the Bengals, a source with knowledge of the situation told NFL.com's Steve Wyche. Zimmer had been expected to draw interest from the Washington Redskins, according to NFL Network's Jason La Canfora.
"I am very excited to have Mike back, coaching our players and directing our defensive staff," Bengals coach Marvin Lewis said in a statement released by the team. "The continuity factor with what we've done and how we plan to keep improving is huge. Mike has the ability to see situations front-to-back, every step and every detail, and he's tremendous at calling the game on Sundays."
The Bengals ranked 27th in the NFL in overall defense in 2007, but they rose to 12th last season, then fourth in Zimmer's second year while winning the AFC North. Cincinnati's defense gave up 301.4 yards per game this season and finished sixth in scoring defense at 18.4 points.
Zimmer coached with a heavy heart this season. Vikki, his wife of 27 years, suddenly died Oct. 8.
"I love working with Marvin," Zimmer said in the statement. "He's a great coach who does a terrific job, and he has been like family to me through all the ordeal our family has gone through. And I really respect the group of players we have. They have worked exceptionally hard, and I know they join me in knowing we have to keep improving as we move forward."
The Associated Press contributed to this report.