He was dismissed during a Monday morning meeting with team president Mike Holmgren, the club said in a statement.
Mangini went just 10-22 with the Browns and finished his second season with a four-game losing streak. Cleveland went 2-6 following an upset of NFL heavyweight New England on Nov. 7 - a victory that seemed like a turning point. Instead, it only triggered a slide.
Mangini's ouster with two years left under contract seemed set long before Sunday's 41-9 loss, and the rout certainly didn't help his cause with Holmgren, the Super Bowl-winning coach who may return to the sideline.
This decision was not easy for me, and it was one into which I put a great deal of thought,'' Holmgren said.Although we have made improvements this season, my responsibility is to ensure that we establish a program that will allow this team to compete at a championship level. That will continue to be our goal in everything we do.''
Holmgren will address the media at 1 p.m.
Mangini's two seasons with Cleveland will be remembered for losing streaks, flickers of hope, injuries and far too much drama for a franchise still looking for a foothold 12 years after its expansion return.
The Browns haven't been able to get it right with a coach since returning to the league; Mangini followed Chris Palmer, Butch Davis and Romeo Crennel on Cleveland's coaching carousel. The instability up top and lack of continuity perhaps best explains the Browns' 64-129 record and one playoff appearance since their rebirth in 1999.
The experience coaching the Cleveland Browns the past two years has been tremendous,'' Mangini said in a statement.I appreciate the opportunity that the Lerner family gave me. I have a deep respect for the players that I have coached the past two years and how they have made a profound difference in changing the culture - a tougher, smarter, more competitive, selfless team that never gave up.
``Our goal was to build a team for long term success. The core characteristics we were dedicated to, I believe, will help achieve that goal, and have provided a strong identity for this football team and have helped to create a positive foundation upon which the organization can continue to build.''
Mangini, 39, inherited a bad situation when he was hired by Browns owner Randy Lerner less than a month after the coach once dubbed ``Mangeunis'' by New York's tabloids was run out of that town following the 2008 season, when the Jets landed short of the playoffs.
For Mangini, the return to Cleveland was a professional homecoming. He began his NFL career with the Browns in the early 1990s as a public relations intern. Eager to learn everything he could to fulfill his dream of coaching, he held a variety of positions under then-coach Bill Belichick.
It was a new start, but Mangini brought some baggage from New York, where the brainy, up-and-coming coaching star quickly lost his shine.
Mangini's first priority in Cleveland was to instill discipline in the Browns, but his heavy handedness rubbed some players the wrong way. He levied fines for violations ranging from a cell phone's ringer going off during a meeting to parking in the wrong spot. He weeded out players he didn't feel would adapt, trading Kellen Winslow and Braylon Edwards - the team's top playmakers. Edwards was famously fined $1,700 for failing to pay for a $3 bottle of water on his hotel bill.
Some Browns complained Mangini's practices were excessively hard, and a few players filed grievances with their union.
He rotated starting quarterbacks last season, but when Derek Anderson and Brady Quinn fell flat, the Browns were 1-11 and it appeared Mangini would be one and done in Cleveland. Then, just as Holmgren arrived, the Browns reeled off four straight wins to end the season, a flurry that bought Mangini another year.
At Holmgren's urging, Mangini loosened up this season. He was more at ease with reporters, and the father of three dropped 50 pounds by ``eating less and exercising more.'' His image was improved, but the Browns weren't any better and with Holmgren waiting in the wings, it seemed it was when, not if, Mangini would be let go.
The week before their bye, the Browns stunned the defending Super Bowl champion Saints in New Orleans, using several trick plays to help rookie quarterback Colt McCoy. One week later, the Browns topped themselves by beating the New England Patriots, a personal triumph for Mangini over Belichick.
At 3-5, the Browns were a long way from a finished product but Cleveland fans were excited again and Mangini's popularity soared. However, the good vibes quickly evaporated. The Browns lost at home in overtime to the Jets on Nov. 14, and a week later, they fell at Jacksonville despite forcing six turnovers.
Cleveland rebounded with victories over one-win Carolina and Miami, but those were overshadowed by losses at Buffalo and Cincinnati where questionable game plans and clock management brought Mangini and offensive coordinator Brian Daboll renewed criticism.
Mangini needed a strong finish like last year to convince Holmgren of real progress, but this time, the Browns collapsed. Back-to-back losses to Baltimore and Pittsburgh dropped him to 2-10 in the division and effectively sealed his fate.
The 32-point blowout defeat by the Steelers was especially troubling as Holmgren watched as Browns fans exited in droves at halftime, leaving thousands of Pittsburgh fans behind to wave their Terrible Towels as the black and gold wrapped up another division title.