Large scale sequencing of cDNAs from a tissue-specific library provides information on the functional phenotype of that tissue and the clones constitute a reservoir of biological markers. For these reasons, we have randomly sequenced 2166 clones of a cDNA library constructed with human colorectal cancer mRNAs. Database searches indicated that 1014 of the cDNAs represented known human genes or human homologs of other genes, 142 sequences corresponded to known ESTs, 119 sequences corresponded to 28S rRNA, repetitive sequences or poly(A) stretches only, and 891 corresponded to unknown transcripts representing the products of 740 new genes. Preliminary studies demonstrated that expression of some of them was altered in cancer. That cDNA collection is therefore a source of potential markers of colorectal cancer.