The sperm coating lizard epididymal secretory protein (LESP) family forms a complex of nine elements that are specifically synthesized under androgenic control and secreted by the epididymal epithelial cells of the lizard Lacerta vivipara. We report here the cloning and sequencing of an 806-base pair full-length cDNA (C731) encoding one of the elements of the LESP family. Southern blot hybridization analysis of lizard total genomic DNA revealed a complex band pattern, suggesting that LESPs are encoded by a multigenic family. The cDNA open reading frame of 516 nucleotides, starting at an ATG codon, encodes a protein precursor of 172 amino acids with a calculated M(r) = 19,500. The corresponding mature form of M(r) = 17,200 and pI = 5.2 has been identified as the element LESP IV, and presents significant similarities to the different members of the large lipocalin protein superfamily, and especially to mouse epididymal protein ESP I. Lipocalins are extracellular proteins that share a common basic framework for the transport of small hydrophobic molecules like retinoids, thus suggesting that LESPs could be such transporters into the epididymal fluid during the sperm maturation.