A new report from the Central Statistics Office shows that fewer than one in five households in Dublin City are now made up of the traditional family unit of husband, wife and children.
However, nationally the number of households composed of the traditional family increased by 3.3%.
The statistics, compiled from information from the Census 2006 also showed that the number of one-person households is up almost 20% since 2002.
They accounted for over 22% of all households in the State last year, and were the predominate unit in the country's five largest cities.
The number of cohabiting couples has increased by more than 44,000 since 2002, making it the fastest growing type of household in Ireland.
The new figures also show that the number of people in their 20s living with their parents fell from 304,353 to 280,065.
The number of those in their 30s still living at home also fell from 70,707 to 65,693.
