Why is Scientology called a religion?
Scientology certainly meets all three criteria generally used by religious scholars around the world to determine religiosity: (1) a belief in some Ultimate Reality, such as the Supreme or eternal truth that transcends the here and now of the secular world; (2) religious practices directed toward understanding, attaining or communing with this Ultimate Reality; and (3) a community of believers who join together in pursuing this Ultimate Reality.
The Scientology view of an Ultimate Reality transcending the material world includes its concepts of the thetan and the dynamics  which include the spiritual world (the Seventh Dynamic) and the Supreme Being (the Eighth Dynamic). The second element can be found in Scientology life-rite ceremonies such as naming , marriage  and funeral  services, but predominantly in the religious services of auditing and training through which Scientologists increase their spiritual awareness and attain an understanding of both the spiritual world and, ultimately, the Supreme Being. As to the third element, a very vital community of believers can be found at any Church of Scientology at almost any time of the day.
Scientology is thus a religion in the most traditional sense of the term. Scientology helps Man become more aware of his own spiritual nature and that of those around him, and, hence, more aware of God.
Scientology carries forward a religious tradition extending ten thousand years and embraces truths found in the oldest sacred texts of the Hindu Veda and the wisdom of Buddhism.
Scientology holds in common with all great religions the dream of peace on Earth and salvation for Man. What is new about Scientology is that it offers a precise path for bringing about spiritual improvement in the here and now and a way to accomplish it with absolute certainty.