To provide information regarding the coding sequences of unidentified human genes, we have conducted a sequencing project of human cDNAs which encode large proteins. We herein present the entire sequences of 100 cDNA clones of unknown human genes, named KIAA1444 to KIAA1543, from two sets of size-fractionated human adult and fetal brain cDNA libraries. The average sizes of the inserts and corresponding open reading frames of cDNA clones analyzed here were 4.4 kb and 2.6 kb (856 amino acid residues), respectively. Database searches of the predicted amino acid sequences classified 53 predicted gene products into the following five functional categories: cell signaling/communication, nucleic acid management, cell structure/motility, protein management and metabolism. It was also revealed that homologues for 32 KIAA gene products were detected in the databases, which were similar in sequence through almost their entire regions. Additionally, the chromosomal loci of the genes were determined by using human-rodent hybrid panels unless their chromosomal loci were already assigned in the public databases. The expression levels of the genes were monitored in spinal cord, fetal brain and fetal liver, as well as in 10 human tissues and 8 brain regions, by reverse transcription-coupled polymerase chain reaction, products of which were quantified by enzyme-linked immunosorbent assay.