Objective: To determine the pattern of intersex disorders manifestable as ambiguous genitalia and the gender assignment of the patients. Design: A retrospective study of patients with ambiguous genitalia to determine the associated intersex disorders and the gender assignment. Setting: King Fahd Hospital of King Faisal University, Al-Khobar, Saudi Arabia. Subjects: Over 10 years 25 patients with ambiguous genitalia were seen. Results: Male pseudohermaphroditism, gonadal dysgenesis and female pseudohermaphroditism occurred in 56%, 8% and 36%, respectively. There were no true hermaphrodites. At birth, 21% and 79% of male pseudohermaphrodites were assigned a male and a female gender, respectively. At puberty, most of these females insisted on masculinization operations, based on their male gender identity and behaviour and their male genotype. The parents of female pseudohermaphrodites, including 22% assigned a male gender at birth, accepted clitoro-vaginoplasty based on the female genotype. Conclusions: Our observation that male pseudohermaphroditism formed the highest proportion of intersex disorders is explained, in part, by the high incidence of patients with pseudovaginal perineoscrotal hypospadias. There is, therefore, a possibility of a cluster of male pseudohermaphroditism due to 5 alpha-reductase deficiency in the Eastern Province making determination of dihydrotestosterone desirable.