Havana is seeking to replace its 1976 constitution to be more in line with modern ideals of socialism rather than Soviet-era communism.
"This does not mean we are renouncing our ideas," National Assembly President Esteban Lazo told state media.
Private property and gay marriage
For the first time, the constitution is set to recognize private property. The current document only recognizes collective forms of property.
Following on the heels of other Latin American countries such as Brazil and Argentina, the new constitution also contains language that recognizes marriage as between two individuals rather than between only a man and a woman.
The office of the presidency will also be changed, with term limits being introduced and some of the president's powers going to the newly created post of prime minister.
The National Assembly is expected to pass the new constitution in the coming days. After its initial approval, the draft will then be open to public consultation, which means it could undergo changes before the final draft is put to a national referendum.
President unveils new cabinet
Although the 86-year-old Castro stepped down as president in favor of his former deputy Miguel Diaz-Canel in April, he remains the most powerful person in the land as the leader of the Communist Party, a position he will hand down to Diaz-Canel in 2021. He was also in charge of the constitutional reform commission.
At the start of the assembly meeting on Saturday, Diaz-Manel also announced his new cabinet, which was later approved by lawmakers. It retains most of Castro's key ministers including the posts of defense, interior, trade and foreign relations.
The most striking omission from the new government was Marino Murillo, one of the vice presidents in Castro's council of ministers. Under Castro, Murillo was responsible for opening up the government-run economy to private and foreign investors.