Chitinases are ubiquitous chitin-fragmenting hydrolases, however until a few years ago that chitinase like proteins have been found in mammalian. A silica-induced bronchoalveolar lavage protein (iSBLP⁵⁸) with fibroblast growth promoting activity in silicotic rat, which had high sequence homology with members of the mammalian chitinase protein family has been previously purified and characterized. Bioinformatics analysis showed that several human EST clones from pooled colon, kidney or stomach matched the rat protein sequence. Thereafter clone from human kidney RNA samples with several pairs of primers was managed and a set of sequences was obtained, whose cDNA and amino acid sequences have high similarity with each other and several human chitinases in GenBank. Comparison with human genome sequence suggests that these molecules may be from variant transcripts of same a Pre-mRNA. Here the characterization of these sequences is reported.