To present the clinical, biochemical, and genetic features of a male pseudohermaphrodite whose condition was caused by 17beta-hydroxysteroid dehydrogenase 3 (17beta-HSD3) deficiency.Case report.Gynecology practice in a university teaching hospital.A 15-year-old black American male pseudohermaphrodite with 17beta-HSD3 deficiency.Laboratory evaluation, genetic mutation analysis, bilateral gonadectomy, and hormone replacement.Endocrinologic evaluation and genetic analysis.A diagnosis of 17beta-HSD3 deficiency made on the basis of hormone evaluation was confirmed through genetic mutation analysis of the HSD17B3 gene. Female phenotype was attained after gonadectomy, passive vaginal dilatation, and hormone therapy.Deficiency of 17beta-HSD3 was diagnosed in this patient on the basis of endocrinologic evaluation and was confirmed with genetic mutation analysis. The patient was able to retain her female sexual identity after surgical and medical treatment.