Since recent past, it has been observed that Indian stock market is experiencing violent fluctuations. In current scenario of Indian stock market each investors is required to be alert enough about happenings in the market. For that purpose it is very important for each and every investor to be aware about major factor affecting stock market. In this paper it has been tried to find out major factors responsible for up and down movements in Indian stock market. From the study it has been found out that factors like flow of foreign institutional investors, inflation, exchange rate are major factors responsible/affecting a movement in Indian stock market.