Speaking today on Vatican Radio, the president said that he had come to Rome for Monday's closing ceremony of the diocesan phase of John Paul II's beatification process.
The president said of his private audience that same day with Benedict XVI: "I spoke with the Holy Father as one of the faithful, and in this way I conducted myself.
"Obviously, we spoke of the cause of beatification of John Paul II."
Kaczynski said that he also told Benedict XVI "of the great significance" the canonization of John Paul II will have for Poland.
The president said Benedict XVI also spoke of "issues linked to the European Constitution and the presence of Christian roots" in the document.
He added: "I assured the Holy Father that we will be faithful to our promises, but I did not guarantee him success."