The team with the best regular season record in 2004 was the Pittsburgh Steelers at 15-1.
The Vikings had the best regular season record in 1998 at 15-1.
The 1972 Miami Dolphins posted a 17-0 record (regular season and playoffs).
That was the St. Louis Cardinals at 100-62. In the American League, the Chicago White Sox had the best regular season record at 99-63.
The Tennessee Titans went 13 & 3.
The team that has the best record or has the best season record.
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.
Through the 2007 season, the American League team with the most wins in a regular season was the 2001 Seattle Mariners with 116. The American League team with the best winning percentage in a regular season is the 1954 Cleveland Indians who went 111-43 for a winning percentage of .721. Seattle's record in 2001 was 116-46 for a winning percentage of .716.