The Bears and Packers are the oldest rivalry in the NFL. In fact, the two franchises pre-date when the league was referred to as the National Football League. The league was known as the American Professional Football Association until the 1922 season.
Since that time, the Bears and the Packers have met 193 times counting both regular and postseason, more than any other teams in the league, including the Bears and the Cardinals, despite the fact that those two teams shared Chicago for decades and that the Bears and Cardinals both joined the AFPA in 1920 and the Packers didn’t come along until 1921.