An underground cavity decorated with seashells, mosaics and pumice stones was discovered near the ruins of the palace of Emperor Augustus on the Palatine hill.
Experts say they are "reasonably certain" it is the long-lost place of worship sacred to ancient Romans and known as Lupercale, from the Latin word for wolf.
"This could reasonably be the place bearing witness to the myth of Rome, one of the most well-known in the world, the legendary cave where the she-wolf suckled Romulus and Remus, saving them from death," said Culture Minister Francesco Rutelli, presenting the discovery.
The cave was found several meters underground in a previously unexplored area during restoration work on the palace of Augustus, the first Roman emperor.
Archaeologists investigating Renaissance descriptions of the sanctuary used a camera probe and the images suggest the vault, which has a white eagle at the centre, is well-preserved.
"You can imagine our amazement, we almost screamed," said Professor Giorgio Croci, the head of the archaeological team working on the restoration of the Palatine hill overlooking the Roman forum, told a news conference.
According to the myth, Romulus and Remus, the twin sons of the god Mars, were abandoned by the banks of the river Tiber where a wolf found them and fed them with her milk.
The brothers are said to have founded Rome at the site on April 21, 753 B.C. and ended up fighting over who should be in charge. Romulus killed Remus and became the first king of Rome.
Archaeologists said the location of the cave reinforced their belief that it was the Lupercale.
"It is clear that Augustus… wanted his residence to be built in a place which was sacred for the city of Rome," said Croci. The emperor had restored the sanctuary and probably connected it to his own palace.
Finding out more about the cave without damaging it or the foundations of the surrounding ruins will not be easy.
More than two-thirds of the cavity, which is some 8 meters (26 feet) high, is filled with debris and earth after part of it collapsed, and it is not clear where the entrance is.
"We have to investigate with extreme caution… This is a precious thing which is certainly more than 2,000 years old," said Croci.
Andrea Carandini, an archaeologist specializing in ancient Rome, said he was stunned by the find and called it "one of the most significant discoveries ever made".
Long accused of neglecting its ancient treasures, the Italian government is spending 12 million euros ($17.7 million) to restore the Palatine ruins.
After being closed for decades due to the risk of collapse, Augustus’s palace will reopen to the public in February 2008.