Human SNAIL1 (SNAI1) protein encoded by SNAI1/SNA gene represses transcription of E-cadherin/CDH1 gene. Human SNAIL2 (SNAI2) protein encoded by SNAI2/SLUG gene induces the first phase of epithelial-mesenchymal transition (EMT), including desmosome dissociation, cell spreading, and initiation of cell separation. Here, we have identified human SNAIL3 (SNAI3) gene using bioinformatics. Human SNAI3 gene, consisting of at least three exons, spans around the nucleotide position 320214-328221 of human reference genomic contig NT_010404.8 in the reverse orientation. SNAI3 gene, was located between KIAA0233 gene and CBFA2T3 gene in human chromosome 16q24.3, a region affected in breast cancer, gastric cancer, hepatocellular carcinoma, ovarian cancer, and therapy-related myeloid leukemia with t(16;21)(q24;q22) translocation. Human SNAI3 gene was found to encode 292-amino-acid polypeptide with the N-terminal SNAG domain and five zinc finger domains. N-terminal SNAG domain was identified in zinc finger proteins SNAI1, SNAI2, SNAI3, SCRATCH (SCRT1), GFI1, and GFI1B. ATP/GTP binding site was identified in SCRT1, GFI1 and GFI1B, but not in SNAI1, SNAI2 and SNAI3. Phylogenetic analysis of human zinc finger proteins with SNAG domain revealed that SNAI1, SNAI2 and SNAI3 were more closely related. These results clearly indicate that SNAI1, SNAI2 and SNAI3 constitute a subfamily among SNAG zinc-finger proteins. Human SNAI3 mRNA was expressed in skin melanotic melanoma, lung epidermoid carcinoma, and germ cell tumor. Because SNAG zinc-finger proteins are transcriptional repressors implicated in carcinogenesis and embryogenesis, SNAI3 gene might be a potent target of pharmacogenomics in the field of oncology and regenerative medicine.