Al-Maqdisi observes of the Khurramites that "the basis of their doctrine is belief in light and darkness"; more specifically, "the principle of the universe is Light, of which a part has been effaced and has turned into Darkness".

They "avoid carefully the shedding of blood, except when they raise the banner of revolt".

They are "extremely concerned with cleanliness and purification, and with approaching people with kindness and beneficience".

Some of them "believed in free sex, provided that the women agreed to it, and also in the freedom of enjoying all pleasures and of satisfying one's inclinations so long as this does not entail any harm to others". (Their name is most frequently derived from the Persian word khurram "happy, cheerful" ).

Regarding the variety of faiths, they believe that "the prophets, despite the difference of their laws and their religions, do not constitute but a single spirit".

Naubakhti states that they also believe in reincarnation (metempsychosis) as the only existing kind of afterlife and retribution and in the cancellation of all religious prescriptions and obligations.

They highly revere Abu Muslim and their imams.

In their rituals, which are rather simple, they "seek the greatest sacramental effect from wine and drinks".

As a whole, they were estimated by Al-Maqdisi as "Mazdaeans... who cover themselves under the guise of Islam".