The mammalian testis determining gene SRY contains an HMG box-related DNA binding motif. By analogy a family of genes related to SRY in the HMG domain have been called SOX (SRY box-related genes). We have cloned and characterized the human SOX11 gene using the partial cloning of both human and mouse SOX11 genes and mapped it to chromosome 1p25. The SOX11 sequence is strongly conserved with the chicken homologue and is related to SOX4. It contains several putative transcriptional either activator or repressor domains. SOX11 expression pattern is consistent with the hypothesis that this gene is important in the developing nervous system.