Acquired primary adrenal insufficiency is a rare disorder in childhood. The most common cause is autoimmune adrenalitis, especially as a part of polyendocrinopathy syndromes. Impaired adrenal function is seen in patients infected with HIV. In adult patients with AIDS, cytomegalovirus (CMV)-associated adrenal insufficiency is a well-known condition, whereas CMV infection as a causing adrenal insufficiency in children is very rare. Here, we report an infant with transient adrenal insufficiency associated with CMV infection but without HIV. She was treated successfully with steroid replacement and ganciclovir. Early diagnosis and treatment is lifesaving in these patients.