There are about 21 major world religions today. About 1 billion people do not profess belief in any religion. Major Religions Chart 1. Christianity 2.1 billion 2. Islam 1.3 billion 3. Secular/Irreligious/Agnostic/Atheist 1.1 billion 4. Hinduism 900 million 5. Chinese traditional religion 394 million 6. Buddhism 376 million (see also buddhism by country) 7. P ...