Croatia received 119 votes, while its regional rival Bosnia-Herzegovina gathered 64.
The Peacebuilding Commission was established in December 2005 as part of the reform of the world body and will focus on peacekeeping, stabilisation, reconstruction and institutional development in countries in transition from war to peace. It has 31 members.
Croatia has great experience in peacebuilding and reconciliation and can offer it to countries emerging from conflict, the Croatian mission to the UN said.