They beat England who, having won it in 2003, were attempting to become the first country to retain the title.
Australia beat England by 163 runs to take a 4-0 lead in the series.
This was the first time they ever had beat England.
Australia beat England by an innings and 9 runs to even the series 1-1.
South Africa beat England by 38 runs in the final to win the competition.
Australia beat England by seven wickets to win the one day series between the two teams.
As a result Ireland became the first foreign team to beat England at home.
Forward was the only change to the previous team that had easily beaten England two weeks before.
Ireland have beaten England six out of the last seven games.
It is the first time since 1927 that the team has beaten England at home.