St Vincent's Health Care is the highest earning charity in Ireland with a gross income of €363m for 2011.
The charity runs St Vincent's University Hospital, St Vincent's Private Hospital, and St Michael's.
Ireland's first Charity 100 Index has been compiled, which reveals the top 100 charities in the country, based on annual turnover.
The top 10 charities are dominated by hospitals. Four of them are voluntary hospitals grant aided by the HSE.
The Index, which also tracks changes in income, revealed an overall decrease in the charity sector of €265m from 2009 to 2011.
Overseas development NGO Bóthar was the biggest faller, dropping 22 places on the Index since 2009.
It is hoped the list, which was compiled by Governance Charity Boardmatch Ireland, will
increase transparency in the sector.