Mozambique's Constitutional Council, the country's supreme court, validated FRELIMO's win in the October election on Monday.
The decision comes after two months of protests in which more than a hundred people were reportedly killed.
The president of the Constitutional Council, Judge Lucia da Luz Ribeiro, proclaimed Daniel Francisco Chapo, candidate of the FRELIMO party, elected President of the Republic of Mozambique.
Opposition protests began in Mozambique immediately after the electoral commission announced preliminary results of the presidential and parliamentary elections held on October 9.