The 1899–1900 St Helens R.F.C.
season was the club's fifth in the Northern Rugby Football Union, the 26th in their history.
In their highest ever finish in a rugby league competition, and their most successful season, the club finished fourth in the Lancashire Senior Championship.
[1] In the Challenge Cup, St Helens were beaten in the first round by rivals Warrington.
[citation needed] However, they did manage some silverware in the season, by beating league winners Runcorn 6-0 in the South Lancashire Cup final.