Proceedings began with the national anthem and speeches were made by visiting dignitaries.
President Raul Castro closed the rally, referring to his brother Fidel as the leader of a revolution "for the humble, and by the humble".
Fidel Castro, who came to power in 1959, died on Friday, aged 90.
Left-wing Latin American leaders were among those attending the event but other countries sent lower-ranking emissaries.
Opinion on Fidel Castro, who ruled Cuba as a one-party state for almost half a century, remains divided.