A nucleotide sequence of broad bean mitochondrial DNA (mtDNA) that contains an atp6 gene of 876 ntp is presented. Relative to other plant atp6 genes, this broad bean gene comprises a 90 ntp non-conserved 5' region, a 759 ntp highly conserved central region and a 27 ntp non-conserved 3' region. The non-conserved, 5' region of the broad bean atp6 gene differs from the corresponding regions of most other plant atp6 genes in that it contains only one potential translation initiation codon and, following this codon, a 63 ntp segment that predicts an amino acid sequence with a predominance of alternating leucines.