The referendum held earlier this month was approved by 86% of voters, the government commission that organized it said on Sunday. Voter turnout was about 64%, it said.
Chad's military authorities have called the vote a vital stepping-stone to elections next year — a long-promised return to democratic rule after they seized power in 2021 when former President Idriss Deby was killed on the battlefield during a conflict with insurgents.
The new constitution will maintain a unitary state, which Chad has had since independence, while some of its opponents had called for the creation of a federal state, saying it would help spur development.
Several opposition groups called for a boycott of the vote, saying the junta had too much control over the referendum process.
Deby initially promised an 18-month transition to elections after his father's death, but last year his government adopted resolutions that delayed elections until 2024 and will allow him to run for president in the eventual vote.