Background: 5-α-ReDuctase (5ARD) deficiency, is an autosomal recessive diseases, resulting in the inability to produce the physiologically active DiHydro Testosterone (DHT) which is required for normal virilization of the male external genitalia. 

Material and Methods: This is a retrospective, hospital based study conducted over a 25 year period (1989-2014) at King Khalid University Hospital (KKUH), Riyadh, Saudi Arabia, where patient’s files with 46 XY, DSD diagnosed with 5-α-reductase deficiency were reviewed for the clinical characteristics and management. All patients were managed by an experienced multidisciplinary team. 

Results: During the period under review, a total of nine (16%) patients among the 56 patients, with 46 XY DSD were diagnosed hormonally, i.e. Human Chorionic Gonadotrophin (HCG) stimulated DHT / testosterone ratio of more than 35, to have 5-α-reductase deficiency. All patients presented with variable degrees of ambiguous genitalia. Unfortunately, three (33.3%) patients needed sex-reassignment. Their clinical characteristics and management were presented. 

Conclusion: In our community, with an increased prevalence of consanguineous matings and with multiple siblings, it is not that an uncommon to have such numbers of 5-α-reductase deficiency among those presenting with 46 XY DSD, and should be considered as an important differential diagnosis. A multi-disciplinary team approach is essential for a successful management and better prognosis.