The Telegraph quoted Patriarch Alexy II as telling MPs at the Council of Europe that civilisation was threatened by a split between Christian morality and human rights, which were being used to excuse declining moral standards.
"We can see it in a new generation of rights that contradict morality, and in how human rights are used to justify immoral behaviour," he told a meeting of the council's Parliamentary Assembly in Strasbourg.
Alexy II went on to say that sinners could be accepted despite their sins, but ignoring the moral teachings of the Bible threatened Europe's standing in the world.
However, he insisted that no state power should interfere with an individual's personal life, saying: "After all, being moral or immoral is a matter of free personal choice."
Earlier this year, Alexy II had banned a gay rights parade through Moscow