The document, entitled "For a Europe of the Citizens: Priorities for a Better Future", defines main guidelines of the EPP policy in the next period.
EPP members advocate the renovation of the project of the European Constitution which came to a halt after it was rejected at referendums in France and the Netherlands.
The document reads that "the debate on the borders of Europe is at the heart of our common European identity".
Regarding the expansion of the European Union, "the balance between the enlargement of the European Union and its consolidation is essential for the viability of the project - otherwise we put at risk the achievements of the past and create enormous difficulties for the future. Therefore, the European Union has to be reformed at latest before the next enlargement, after Romania and Bulgaria".
The EU needs thorough reforms in its economy and common security and defence policy, it is noted in the document.
The Rome congress and study days marked the 30th anniversary of the EPP group. On that occasion, Wilfried Martens was re-elected EPP president.
At the Rome event Croatia was represented by Prime Minister Ivo Sanader, who is the chief of the Croatian Democratic Union (HDZ), which is an associate member of the group, and Josip Friscic, the chief of the Croatian Peasant Party (HSS), which has observer status just as another Croatian party, the Democratic Centre (DC).
At the end of the congress, Sanader voiced satisfaction with the EPP convention.
The culmination of the event for Croatia was the adoption of a resolution on the country's fast-track accession to the union, according to Sanader.
"We can be satisfied with the fact that the resolution supporting Croatia's EU membership bid was adopted," Sanader told Croatian reporters this evening.
"The strongest European force has unequivocally committed itself to Croatia's EU membership," the PM added.
There is no mention of Croatia in the manifesto, but Sanader said that the adoption of a separate resolution on his country's accession efforts "is a much stronger (message) than if Croatia were mentioned as one of about 30 chapters in the Rome manifesto".
With Croatia's accession the reunion of the European family will be fuller, reads the first point of the resolution.
The EPP hails the opening of Croatia's accession negotiations with the EU and advocates the assessment of each candidate country on its own merits.
The five-point resolution confirms that Croatia should continue the accession negotiations with the EU and welcomes Croatia's readiness to encourage free trade through the enlargement of CEFTA (Central European Free Trade Agreement) with the aim of ensuring European prospects for Croatia and its neighbours in southeast Europe.
Sanader said that EPP president Martens would attend a convention of the HDZ in Vukovar on Saturday.