The tomb was located at the bottom of a 36-foot deep shaft, said top archaeologist, Zahi Hawass. Twenty-two mummies were found in niches along the tomb's walls, he said.
Eight sarcophagi were also found in the tomb. Archaeologists so far have opened only one of the sarcophagi - and found a mummy inside of it, said Hawass' assistant Abdel Hakim Karar. Mummies are believed to be inside the other seven, he said.
The "storeroom for mummies" dates back to 640 B.C. during the 26th Dynasty, which was Egypt's last independent kingdom before it was overthrown by a succession of foreign conquerors beginning with the Persians, Hawass said. But the tomb was discovered at an even older site in Saqqara that dates back to the 4,300-year-old 6th Dynasty, he said.
Most of the mummies are poorly preserved, and archeologists have yet to determine their identities or why so many were put in one room.
The name Badi N Huri was engraved into the opened sarcophagus, but the wooden coffin did not bear a title for the mummy.
"This one might have been an important figure, but I can't tell because there was no title," Karar said.
Karar also said it was unusual for mummies of this late period to be stored in rocky niches.
"Niches were known in the very early dynasties, so to find one for the 26th Dynasty is something rare," he said.
Excavations have been ongoing at Saqqara for 150 years, uncovering a necropolis of pyramids and tombs dating mostly from the Old Kingdom but also tombs from as recent as the Roman era.
In the past, excavations have focused on just one side of the site's two most prominent pyramids - the famous Step Pyramid of King Djoser and that of Unas, the last king of the 5th Dynasty. The area where the current tomb was found, to the southwest, has been largely untouched by archeologists.
In December, two tombs were found near the current discovery of mummies. The tombs were built for high officials - one responsible for the quarries used to build the nearby pyramids and the other for a woman in charge of procuring entertainers for the pharaohs.
In November, Hawass announced the discovery of a new pyramid at Saqqara, the 118th in Egypt, and the 12th to be found just in Saqqara.
According to Hawass, only 30 percent of Egypt's monuments have been uncovered, with the rest still under the sand.