The sex-determining region of the Y chromosome (SRY) gene initiates the process of male sex differentiation in mammalians. In humans, mutations in the SRY gene have been reported to account for 10-15% of the XY sex reversal cases. In this report we describe the clinical, endocrinological and molecular data of a patient with complete 46,XY gonadal dysgenesis caused by a de novo mutation affecting SRY amino acid phenylalanine at position 67 (F67L), located within the highly conserved high mobility group (HMG) box coding region of the gene.