The nucleotide sequence of a 2.0 kb cDNA encoding a rabbit sperm tail membrane protein was determined using the chain termination method. Analysis was performed using Sequenase and Klenow enzymes on the target sequence in an M13mp18/19 cloning system. The open reading frame consisted of 438 bp encoding 146 amino acids of the protein, with a calculated Mr of 15507. The hydrophobic amino acid content was 34.9%, and pI was in the vicinity of 5.8.