Evidence of relative sea-level fluctuations during the Upper Quaternary are represented by numerous geological, biological, and pre-historical (shell-middens) records found along the Brazilian coast line. About 700 of these records, dated mostly by the radiocarbon method, are distributed through the States of Alagoas, Sergipe, Bahia, Espírito Santo, Rio de Janeiro, São Paulo, Paraná, and Santa Catarina. The coastal plains of these states, representing about 50% of the Brazilian coast, have been geologically mapped, in part or entirely during the last 10 years. The geological maps are accompanied by sea level fluctuation curves for the past 7,000 years for the States of Bahia (Salvador, Ilhéus, and Caravelas sectors), Rio de Janeiro (Angra dos Reis sector), São Paulo (Santos and Cananéia-Iguape sectors), Paraná (Paranaguá sector) and Santa Catarina (Itajaí-Laguna sector). These informations allowed us to know that the relative sea level fluctuations during the last thousand years played a very important role in the construction of the Brazilian Coastal plains. It was also demonstrated that the relative sea level fluctuations during the Upper Quaternary have been important for the construction of the river mouth coastal plains of São Francisco (SE/AL), Jequitinhonha (BA), Doce (ES) and Paraíba do Sul (RJ) rivers, whose evolutionary histories were quite different in relation to the classical delta plains presented in the geological literature.Resumo indisponível.