In contrast, the oldest population was recorded in Germany
Ireland has the youngest population in the EU, with an average age of 36 years.
Eurostat found the average age across the entire union in 2014 was 42.2 - meaning half of the population was younger and half was older than that.
Following Ireland's youthful example are Cyprus (36.8 years), Slovakia (38.6 years), Luxembourg and Poland (both 39.2 years) and the UK (39.9 years).
In contrast, the oldest population was recorded in Germany at 45.6 years.
Italy, Bulgaria, Portugal and Greece round out the oldest five.
Eurostat says that over the last 20 years, the median age of the EU population rose by six years - from 36.2 years in 1994.
"This trend was noticeable in all member states, in particular in Lithuania, where it rose by almost nine years since 1994. Increases of seven years or more were observed in Germany and Portugal, as well as in Austria and Romania", it adds.
It also found that one-third of EU households are made up of just one person - highest in Denmark, Finland and Sweden - while more than 40% of those living alone in the EU are aged 65 or over.
In eight states, those aged 65 or over were even in the majority: that is in Croatia, Romania, Portugal, Bulgaria, Latvia, Lithuania, Malta and Slovakia.