The turnover of Irish-owned multinationals reached €238bn in 2020, down 7% when compared to the previous year.
New figures from the Central Statistics Office (CSO) show the US generated more than 39% of such turnover, while almost 17% was generated from the UK.
Irish-owned foreign affiliates employed more than 1.2 million people in 2020, up almost 3% on 2019.
Almost 22% of such employees were in the US, while almost 10% were in the UK.
The services sector, excluding distribution, accounted for the highest turnover and employment in these companies in 2020.
Devin Zibulsky, Statistician in the Business Statistics Division pointed out that Irish-owned foreign affiliates reported a lower overall turnover in 2020 than in the three previous years.
"Many enterprises were impacted by the Covid-19 pandemic, including multinationals," he said.