Ayatollah Mohammad Emami Kashani, Tehran's Friday prayer leader, was referring to the Western phenomenon of holding parties to celebrate the dissolving of a marriage, a practice that has recently emerged in the Islamic republic.
Kashani told worshippers that marriage is a sacred bond and that Western practices like divorce parties undermine family values.
Iranian media in recent days have reported on extravagant preparations for such parties, including black roses and cakes.
"Unfortunately, divorce parties are being organised as of recently...This is very dangrous. It's a poison for the Islamic civilization and society," Kashani said in his Friday prayer sermon, which was broadcast live on state radio.