The cemetery, which dates back to the early Greco-Roman era, is believed to contain more than 10,000 mummies, making it the biggest uncovered, Egypt's Middle East News Agency (Mena) reported yesterday.
The area, within the city of Bawiti, 185 miles south-west of Cairo, has been renamed Valley of the Mummies, the news agency said.
Fifty mummies were found in each of four rooms. They included wealthy people and some rulers, Gaballah Gaballah, head of the Supreme Council of Antiquities, told Mena.
Some of the mummies had golden masks, others were covered with plaster or resting in pottery coffins.
The cemetery is four miles long, and Zahi Hawass, head of the 12-member discovery team, told Mena that it took four years to uncover the first 200 mummies. Work will continue until the rest are uncovered, he said.
Mohammed al-Saghir, head of Pharaonic antiquities in Egypt, confirmed the discovery for the Associated Press, but said he had no details.
Mr Hawass said studies on one of the mummies determined the remains were of a 50-year-old man who did not appear to have been sick.
A wine factory was also discovered and several pieces of pottery, Mena reported. (AP)