Taoiseach Bertie Ahern is in Brussels for talks with the parliament's president, Mr Josep Borrell.
Mr Ahern will also make a key-note address to the parliament itself where he is expected to concentrate on challenges facing the EU and Ireland's increasing role within the 25-state bloc.
The Taoiseach will also meet with EU political party leaders and Irish MEPs.
Speaking ahead of today's address, Mr Ahern said: "It is a great honour to address the only directly-elected, multi-national legislative body in the world."
"The significance of the Parliament in today's Europe was borne out recently by the constructive role it played in ensuring that a compromise was reached on the EU Services Directive."
