The elongation factor EF-1 α is one of the most studied components of the translation machinery owing to its abundance and possible role in other cellular functions. EF-1 α mediates the correct coupling of the aminoacyl-tRNA on the A site of the ribosome in a GTP-dependent reaction. We have previously described an EF-1 α DNA sequence in Leishmania amazonensis, pLEF11 (accession No. M92653), using PCR. In this paper we describe the DNA sequence and genomic organization of L. braziliensis EF-1 α gene. Southern blot analysis revealed that EF-1 α is organized as a 2 kb tandem repeat. The pLEF11 probe recognized a 1.8 kb mRNA from promastigotes in Northern blots. A clone containing the first copy and a half of the EF-1 α tandem repeat was isolated by screening a L. braziliensis genomic library. Southern blot analysis showed that the isolated clone ( λ2.2) presented the same hybridization profile as that of a genomic blot. The partial sequencing of clone λ2.2 spans 2959 nucleotides in length, which has two open reading frames separated by a putative non-coding region. The nucleotide and the predicted peptide sequence of the first coding region presented approximately 80% identity with other eukaryotic EF-1 α genes. The sequence also displayed the four consensus motifs corresponding to the GTP-binding site (G1, G2, G3 and G4). Computer analysis of the sequence of both coding regions revealed three divergent nucleotides, which generated two changes at the amino acid level. One was found to be located in the G2 domain. The non-coding region of the EF-1 α gene sequence showed potential regulatory elements such as polypyrimidine tracks, chi-homologous sequences and stem-loop forming sequences.