The average farm income was €21,500 this year, a drop of 12 per cent since 2011, according to the latest estimates from Teagasc.
The research and advisory body said there were "very significant" variations on individual farms, with major falls in income recorded on dairy and tillage farms.
Wet weather had a particular impact on farming in the east and south, where tillage and dairying are most prevalent.
Income on beef farms increased marginally with prices remaining relatively strong throughout the year.
Teagasc economists predicted that the average farm income would rise next year but said the percentage increase would be in the single digits.
