DNA sequences homologous to adult alpha-globin genes are dispersed in the mouse. Two functional genes are tightly linked on chromosome 11. Pseudogenes have been assigned to chromosomes 15 and 17 by analysis of interspecies somatic cell hybrids. We have now further characterized the second of these pseudogenes, Hba-a4. The gene is highly polymorphic, with three forms occurring in a panel of 15 inbred strains and a fourth occurring in an inbred strain derived from M. m. molossinus. Analysis of Hba-a4 alleles in CXB, BXH, and AKXL recombinant inbred strains placed Hba-a4 6.60 +/- 3.14 cM centromeric to H-2. Analysis of congenic mouse strains confirmed the linkage and the gene order. Hba-a4 is the first mammalian dispersed pseudogene to be localized in a linkage map, and should provide a useful marker for the region of chromosome 17 proximal to H-2.