New figures from the Central Statistics Office show that the southeast was the poorest region in the country in 2004.
The report, which measures disposable income per person in the State's eight regions, found that the southeast was 8.8% below the State average.
The Dublin region had the highest income per person, at almost 12% above the average.
A county breakdown showed that only Dublin, Cork, Limerick and Kildare had an income per person above the State average.
The lowest county figure was for Donegal where average disposable incomes were almost 15% below the average.