Investigators approaching the problem of renal organogenesis have been hampered by a paucity of suitable molecular markers that specify distinct developmental phenotypes. To identify such markers, differential display-polymerase chain reaction (DD-PCR) was used to survey the temporal pattern of gene expression in mouse kidney at 11.5, 13.5, 15.5, and 17.5 days after conception and in the adult kidney. Twenty-two differentially expressed amplification products were identified, isolated, and sequenced. Seventeen clones showed no significant similarity with previously reported nucleotide sequences: two were similar to two housekeeping gene products, and three were similar to human or rat expressed sequence tags. To confirm the differential expression patterns observed by DD-PCR, semiquantitative reverse transcription-PCR was performed using sequence-specific oligonucleotide primers. Nineteen of 22 clones were differentially expressed during kidney development [mouse embryonic renal marker (MERM) sequences 1-19]. The value of MERMs as developmental markers was further assessed in mouse metanephric organ culture, where the pattern of MERM transcript expression mimicked that observed in vivo. Therefore, the DD-PCR method permitted development of a panel of marker sequences that can be used to characterize renal developmental processes and that may allow the identification of novel, functionally relevant gene products.