The Drepung Monastery, the Ganden Monastery and Sera Monastery are collectively called as Big Three Monasteries. The monastery was founded in 1416 by a disciple of Tsong Khapa under the patronage of a noble family and later enlarged by the Fifth Dalai Lama. The second, third and forth Dalai Lama once stayed here. In the ninth year (1530) of the Jiajing reign of the Ming Dynasty (1368-1644), the Ganden Palace (Ganden Potrang) was built as the living room of Dalai Lama, who took charge of the power over major religious and political issues in Tibet.

The monastery has a large scale with an area of 250,000 square meters. The main structures of the monastery include the Main Assembly Hall (known as Tshomchen), four Tantric colleges and Ganden Palace (Ganden Potrang). The tshomchen of Drepung, covering 4,500 square meters and supported by 183 pillars in the center of the monastery, is the best known, most powerful tschomen of all the monasteries in Tibet. It can seat 8,000 monks. In addition, a great deal of ancient books and sutras are preserved in the monastery.