Blair leaves office on Wednesday.
The statement, issued after the talks with Benedict and a separate meeting with Tarcisio Bertone, secretary of state cardinal, said there was a "frank" assessment of the international situation.
The discussion is understood to included such themes as the Middle East conflict and the future of the EU.
The Vatican opposed the US-led invasion of Iraq, which Blair supported.
The statement said that Blair has expressed the desire "to dedicate himself in a particular way for peace in the Middle East and for inter-religious dialogue."
Blair's life after Downing Street has been a matter of speculation.
Earlier this week, it was suggested that George Bush, the US president, wants Blair to take the job of Middle East envoy for the Middle East Quartet.
Al Jazeera reported last week that Blair was recommended to join of peacemakers, comprising the US, Russia, the EU and the UN.
Downing Street has refused comment on the reports.