Benedict XVI, as the Supreme Shepherd of the Church and the head of the Vatican state (Vatican City), maintained contacts with representatives of the authorities of Muslim countries or those dominated by Islamic culture. He supported and built good relations between representatives of different religions, including Islam, through openness and honesty in the interreligious dialogue and bearing witness to the essential values of Christianity and Islam – justice and peace. In the article, we indicated the essence, purpose and challenges of interreligious dialogue, especially dialogue with Islam. People and environments involved in its conduct should be guided by the idea of searching for the true good of man and society. At the same time, it is important to remain faithful to one’s own religious identity, especially on the doctrinal level. Dialogue, in fact, should aim, first of all, at seeking the truth and bearing witness to it. This will only be possible if you respect your own faith and show respect for the identity of the followers of Islam. In the dialogue with Islam, the most important is Almighty God, who must be given his rightful place. For faith in one God obliges His believers to be responsible for peace. Benedict XVI’s theory of dialogue found confirmation in the papal meetings, either with the “world of Islam” or with various bodies (ecclesiastical, political, people involved in the so-called dialogue of specialists). For Benedict XVI, the most important criterion for dialogue was fidelity to Christian identity.