Through the 2010 season, it's the Chicago Bears. They have a record of 704-512-42 for a winning percentage of .579.
49ers
Pittsburgh Steelers
the colts have the highest winning precentage
85%
bucanners
Among existing teams, the Cowboys have the best winning percentage. As of the beginning of the 2010 season, Dallas is 467-339-6 all-time, for a .579 winning percentage.
Philadelphia Eagles
SF 49ers
Tom Brady and Ben Roethlisberger are the two quarterbacks that have the best winning percentage in their first 4 years in the NFL. Ben Roethlisberger has the fourth highest career winning percentage as a quarterback.
According to the Pro Football Hall of Fame, as of the start of the 2007 season the team with the best all time regular season winning percentage was the Miami Dolphins whose all time regular season record was 368-252-4 for a winning percentage of .593. Second was the Chicago Bears with an all time regular season record of 670-482-42 for a winning percentage of .579.
Seattle Seahawks .500
A '500 team' is a team that has won the same number of games as they have lost. The '500' refers to the team's winning percentage.