Atheistic schools are found in Hinduism, which is otherwise a very theistic religion. The thoroughly materialistic and anti-religious philosophical Cārvāka School that originated in India around 6th century BCE is probably the most explicitly atheistic school of philosophy in India. This branch of Indian philosophy is classified as a heterodox system and is not considered part of the six orthodox schools of Hinduism, but it is noteworthy as evidence of a materialistic movement within Hinduism.[60] Chatterjee and Datta explain that our understanding of Cārvāka philosophy is fragmentary, based largely on criticism of the ideas by other schools, and that it is not a living tradition:
"Though materialism in some form or other has always been present in India, and occasional references are found in the Vedas, the Buddhistic literature, the Epics, as well as in the later philosophical works we do not find any systematic work on materialism, nor any organized school of followers as the other philosophical schools possess. But almost every work of the other schools states, for reputation, the materialistic views. Our knowledge of Indian materialism is chiefly based on these."[61]
Other Indian philosophies generally regarded as atheistic include Classical Samkhya and Purva Mimamsa. The rejection of a personal creator God is also seen in Jainism and Buddhism in India.[62]
http://en.wikipedia.org/wiki/Atheism#Early_Indic_religion