Pulmonary surfactant, a protein-phospholipid mixture, maintains surface tension at the lung epithelium/air interface preventing alveolar collapse during respiration. For mammals appropriate developmental production of surfactant is necessary for adaptation to the air breathing environment. Deficiency of pulmonary surfactant results in respiratory distress syndrome (RDS), a leading cause of death in premature infants. Recently, three lung-specific pulmonary surfactant proteins designated SP-A, SP-B, and SP-C have been described. Cloned sequences for the genes that encode each of these proteins have been partially characterized in humans and other species. Analysis of interspecific backcross mice has allowed us to map the chromosomal locations of these three genes in the mouse. The gene encoding SP-A (Sftp-1) and the gene encoding SP-C (Sftp-2) both map to mouse chromosome 14, although at separate locations, while the gene encoding SP-B (Sftp-3) maps to chromosome 6. The mouse map locations determined in this study for the Sftp genes are consistent with the locations of these genes on the human genetic map and the syntenic relationships between the human and the mouse genomes.