Mapping of the human ribosomal protein (RP) genes has been completed, and all 80 different genes were placed on a cytogenetic map of the human genome. Because of the existence of processed pseudogenes, the localization of the RP genes was complicated, and five genes had remained to be mapped. Here we developed a novel strategy to identify sequence-tagged sites (STSs) at introns of the RP genes, and we localized RPL14, RPL22, RPL35, RPL36, and RPL39 within the chromosomes by radiation hybrid mapping. Unlike the case of eubacteria or archaebacteria, human RP genes are widely scattered about the genome. Together with the previous results, both sex chromosomes and 20 autosomes (all but chromosomes 7 and 21) were found to carry one or more RP genes. To explore the possible involvement of RP genes in human disorders, all 80 genes were assigned to cytogenetic bands according to a published cytogenetic BAC-STS map of the human genome. We compared the assigned positions with candidate regions for Mendelian disorders and found certain genes that might be involved in particular human disorders.