The 2005 Chatham Cup was the 78th annual nationwide knockout football competition in New Zealand. Up to the last 16 of the competition, the cup was run in three regions (northern, central, and southern), with an open draw from the quarter-finals on. In all, 129 teams took part in the competition. The numbering of rounds in the competition is unclear — some sources record one preliminary round and four full rounds, followed by quarter-finals, semi-finals, and a final; other sources record five rounds. The latter numbering is used in this article.