The 1904–05 Challenge Cup was the 9th staging of rugby league's oldest knockout competition, the Challenge Cup.

[1] Warrington, the previous year's beaten finalists, won the Cup at their third attempt.

[2] The final was contested by Warrington and Hull Kingston Rovers at Headingley in Leeds[3] on Saturday 29 April 1905, in front of a crowd of 19,638.

[4] Warrington beat Hull KR 6–0.