Zoroastrianism is the religion and philosophy based on the teachings ascribed to the prophet Zoroaster (Zarathustra, Zartosht). Mazdaism is the religion that acknowledges the divine authority of Ahura Mazda, proclaimed by Zoroaster.
As demonstrated by Zoroastrianistic creed and articles of faith, the two terms are effectively synonymous. In a declaration of the creed — the Fravarānē — the adherent states: "…I profess myself a devotee of Mazda, a follower of Zarathustra." (Yasna 12.2, 12.8)
While Zoroastrianism was once the dominant religion of much of Greater Iran, the number of adherents has dwindled to not more than 2,000,000 and about 200,000 parsis worldwide, with concentrations in India and Iran (see demographics below).
