Castro's cremated remains were due to be placed a few steps from the mausoleum of independence hero Jose Marti.
A private ceremony was held at Santiago's Santa Ifigenia Cemetery, state media reported.
Castro's cremated remains were due to be placed a few steps from the mausoleum of independence hero Jose Marti, another towering figure of Cuban history who Castro long admired.
Castro died on Nov. 25 aged 90. He had been out of power for a decade but never far from the center of public life, writing a periodic column on world and local matters and receiving foreign dignitaries at his home on the outskirts of Havana.
He gave Cuba an outsized influence in world affairs, but leaves a mixed legacy. He was feted by Nelson Mandela for helping end apartheid at a time the West supported the racist system, but also helped take the world to the brink of nuclear war during the Cuban missile crisis.
Forced to step down due to an intestinal ailment, Castro ceded power to his younger brother, current President Raul Castro, at first provisionally in 2006 and then definitively in 2008. Cuba has not revealed the cause of his death.
In keeping with his wishes, Castro's image will not be immortalized with statues nor will public places be named after him, his brother said on Saturday.
Initially the act at the cemetery was due to be carried live on television, but hours before official media announced it would be "solemn and private."
Cuban television cut from live coverage at the appointed hour of 7 a.m. EST (1200 GMT). At that moment in Havana, military cannons unleashed a 21-gun salute that thundered across the capital city.