This is a list of all seasons played by Cambridge United in English football since the 1970–71 season, when the club were elected to the Football League. It details their record in every major competition entered, as well as the top goalscorers for each season.
The club currently play in League One, having been promoted from League Two in 2020/21 where they had competed since 2014, following their promotion back to the Football League after a 9-year absence, during which time they competed in the Football Conference.
The club has spent the following number of seasons at each level of the English football league system since its initial election:
Seasons at level 2: 8
Seasons at level 3: 11
Seasons at level 4: 22
Seasons at level 5: 9
The club's highest position ever is 5th in the Second Division in 1991–92, the last season before the establishment of the Premier League, a playoff position. They lost the semi-final to Leicester City 6–1 on aggregate and lost their chance to become founder members of the Premier League. Their lowest position has been 17th in the Football Conference (now National League) in 2006–07 and 2010–11.