The unexpected arrival of an infant with ambiguous genitalia is stressful for both physicians and parents. Careful assessment of the external genital structures and the overall infant directs the immediate management. Investigations include evaluation of glucose, electrolytes, chromosomes, and 17-ketosteroids as well as ultrasound and evaluation of the urinary tract as appropriate. The review of family and pregnancy history addresses concerns regarding medications or previously affected infants. The most efficient method of evaluating such an infant is by a team approach, with each team member contributing expertise and one communicating with the family and the family physician. Unnecessary overlap of investigations can be avoided as well as rash decisions as to sex of rearing. Counseling the family provides support during the stressful first days until decisions can be made about information regarding the diagnosis and prognosis of the infant, recurrence risk figures for subsequent pregnancies or other family members, and whether prenatal diagnosis might be appropriate. The family can be helped to move through the ordeal with their child and develop trust in the team members.