The 1988 Constituent Assembly (Portuguese: Assembléia Constituinte de 1988), also known as the National Constituent Assembly (Portuguese: Assembléia Nacional Constituinte) was held in Brasília to establish Brazil's new democratic Constitution after 21 years under military rule. In November 1986, general elections were held to elect the members of the constituent assembly, which took office on February 1, 1987. Ulysses Guimarães, from the Brazilian Democratic Movement Party of São Paulo, served as president of the Assembly.

National Constitutional Assembly Assembleia Nacional Constituinte
Type
Type	Unicameral constituent assembly
History
Founded	February 1, 1987 (1987-02-01)
Disbanded	July 22, 1988 (1988-07-22)
Leadership
President	Ulysses Guimarães, PMDB
1st Vice President	Mauro Benevides, PMDB
2nd Vice President	Jorge Arbage, PDS
Structure
Seats	559 constituents
Political groups	Majority   PMDB (303)   PFL (135)   PDS (38)   PTB (18)   PL (7)   PDC (6)   PSC (1)   PMB (1) Minority   PDT (26)   PT (16)   PCdoB (3)   PCB (3)   PSB (2)
Authority	Constitutional Amendment no. 26 of November 27, 1985
Elections
Voting system	Open list proportional representation (Deputies) Dual-member block voting (Senators)
Last election	November 15, 1986
Meeting place
Nereu Ramos Palace Brasília, Federal District, Brazil

The majority in the Constituent Assembly was formed by the Democratic Centre (PMDB, PFL, PTB, PDS, and smaller parties), also known as "Big Centre" (Centrão). They were supported by the executive branch and represented conservative factions of the society, and had a decisive influence in the work of the Constituent and the outcome of important decisions, such as the duration of then President Sarney's term, the maintenance of the agrarian policy and the role of the Armed Forces.