Scientists worked for a decade to rehabilitate the pyramid and tombs discovered in 1927, officials said.
"I am very happy today to reopen these tombs which were closed for more than 10 years due to restoration," Ministry of State for Antiquities chief Mohamed Ibrahim said in a ceremony at the site Thursday.
Included in the restored historic site is the tomb of the granddaughter of King Khufu, builder of the Great Pyramid, along with those of five Old Kingdom noblemen.
The tombs feature impressive facades and resemble temples with large chambers supported by rock-hewn pillars, officials said.
"Although these tombs may be sparse in decoration, they are rich in architectural features," Ali El-Asfar, the director general of Giza antiquities department, told Ahram Online.
In the $4 million restoration project the walls of the tombs were cleaned and reinforced, graffiti was removed and inscriptions and paintings conserved, Ibrahim said.