We report the complete sequence of the rabbit reticulocyte (RBC) 15-lipoxygenase (LOX) mRNA as deduced from (i) sequencing cDNA recombinants isolated by screening cDNA libraries or polymerase-chain-reactions, and (ii) the sequence originating from the transcription start point obtained by primer extension-sequencing reactions. Like the human leukocyte 5-LOX mRNA, the RBC 15-LOX mRNA contains a very short 5'-untranslated region with a long 3'-untranslated region. But, unlike the human leukocyte 5-LOX mRNA, the RBC 15-LOX mRNA contains an intriguing repeated sequence (ten copies with the consensus sequence C4PuC3TCTTC4AAG) just after the translational stop codon, which may be involved in its regulation during reticulocyte maturation. Comparison of the RBC 15-LOX mRNA sequence with those of the previously published human 5-LOX mRNA and the soybean 3-LOX gene shows only a few short regions of sequence similarity. However, the predicted amino acid sequences of the encoded LOX enzymes show certain conserved regions that are presumably involved in their catalytic activity, in particular a cluster of five conserved histidines that we predict chelate the iron moiety involved in the active site.