He also commended Croatia for its participation in the NATO-led ISAF mission in Afghanistan which he described as the alliance's top operational priority.
Croatian troops participation in the mission in Afghanistan deserve every praise, Scheffer said.
Commenting on Croatia's admission to NATO, he said that Croatia had joined "the unique family of democratic countries".
He added that it was Croatia's great success to have its leaders, President Stjepan Mesic and Prime Minister Ivo Sanader, participating in the alliance's summit meeting in Strasbourg and Kehl on Friday and Saturday.
"All is well that ends well," he said when asked to comment on problems during the process of ratification of Croatia's accession protocol in Slovenia which could have delayed Croatia's entry into the alliance.
According to him, Croatia will be engaged in all major political discussions at the forthcoming summit.
He said that he, as well as the Slovene government, had always wanted Croatia and Albania to enter the alliance.
He added that the organisation's open-door policy would be in place for all those meeting its membership criteria.