Scientists at the University of Oxford in Britain say radiocarbon dating and computer models suggest the civilization's first ruler, King Aha, came to power in about 3100 B.C.
The pre-dynastic period, when early groups began to settle along the Nile and farm the land, had been thought to have began in 4000 B.C.
The new study revealed this process started later, between 3700 and 3600 B.C., and the society had transformed into one ruled by a king just a few centuries later.
"The time period is shorter than was previously thought -- about 300 or 400 years shorter," Oxford's Michael Dee told the BBC. "Egypt was a state that emerged quickly -- over that time one has immense social change.
"The formation of Egypt was unique in the ancient world. It was a territorial state; a state from which the moment it formed had established borders over a territory in much the same way we think of nations today," he said. "This is interesting when one compares it with other places. In Mesopotamia, for example, you have agriculture for several thousand years before you have anything like a state."