Although they have not yet had the time or the access to identify the tomb, one of the archaeologists said it contained five or six mummies in intact sarcophagi from the late 18th dynasty - about the same period as Tutankhamun.
The 18th dynasty ruled Egypt from 1567BC to 1320BC, a period during which the country's power reached a peak.
The Valley of the Kings in southern Egypt contains the tombs of most of the pharaohs of the time but the archaeologist said the mummies in the newly found tomb will not necessarily be royal.
The archaeologist said: "There are lots of non-royal tombs in the valley. It wouldn't be the only one by any means."
Egypt's Supreme Council of Antiquities issued a statement saying the five sarcophagi, which are carved to human form, have coloured funerary masks and the tomb contains many large storage jars.
It said that for an unknown reason they were buried rapidly in the small tomb.
The tomb, 5km from that of Tutankhamun, was covered with the rubble of workmen's huts dating from the latter part of the 19th dynasty, more than 100 years after the tomb was sealed.