Carine Bachmann, director of the Swiss Federal Office of Culture, handed over the fragment to the Egyptian embassy in the capital, Bern.
It had been confiscated in Geneva as part of criminal proceedings, and was restituted to Egypt under Switzerland's law on the international transfer of cultural property.
"The stone sculpture of pharaoh Ramses II is part of a group statue where the king sits alongside different Egyptian deities," the culture ministry said in a statement.
"The fragment was stolen between the late 1980s and early 1990s from the Temple of Ramses II at Abydos in Egypt. It transited through different countries before arriving in Switzerland."
The culture ministry said Egypt was heavily affected by the looting and destruction of its archaeological sites, with historical objects from the north African country being highly coveted.
"This restitution underlines the joint commitment of Switzerland and Egypt to combat the illicit trade in cultural property," the ministry said.
Ramses II, also known as Ramses the Great, ruled for more than 60 years during the 13th century B.C. and oversaw major military conquests and monumental construction projects, while also finding time to father more than 100 children.
His ornate sarcophagus is on display in Paris from April to September, as part of a touring exhibition.
The mummy itself has stayed behind, since Egyptian law now forbids transporting royal mummies abroad.
Ramses II Statue Piece Returned to Egypt
FILE: A huge granite statue of Ramses II (center) after the completion of restoration work, south of Cairo, Egypt, taken April 18, 2017.
GENEVA — Switzerland on Monday handed back to Egypt a fragment of a 3,400-year-old statue of the ancient Egyptian pharaoh Ramses II, which was stolen more than 30 years ago.