Interleukin-8 (IL-8), a member of the chemokine alpha subfamily, is a chemoattractant for neutrophils. Cell surface receptors for IL-8 have been cloned from rabbits and humans. Two related but different IL-8 receptors (IL-8R) have been characterized from humans. IL-8RA and IL-8RB bind IL-8 at high affinity but IL-8RB also binds GRO/MGSA and NAP-2 at high affinity. Using the human IL-8RB cDNA as a probe, we have determined that the homologous murine gene maps near the Ity-Lsh-Bcg disease resistance locus. A murine homologue of the human IL-8RB was isolated from a genomic library. This gene would encode a protein of 359 amino acids and would have a 68 and 71% amino acid identity with human IL-8RA and IL-8RB, respectively. Additional mapping data using the murine gene revealed the following genetic distances (in cM +/- 1 standard error) from the centromere: Mylf--7.9 +/- 2.7--Lsh-Ity-Bcg--1.9 +/- 1.4--Il8rb--1.9 +/- 1.4--Vil-- 5.9 +/- 2.3--Acrg--2.9 +/- 1.7--Bcl-2.