We describe a female newborn infant with McCune-Albright syndrome. In addition to the cutaneous pigmentation, she had apparent manifestations of hyperthyroidism and Cushing syndrome since birth. X-ray examinations showed many scattered lucencies in multiple bones. Endocrinological findings were as follows: serum T 4 276 nmol/l; free T 4 125 pmol/l; TSH less than 1 mU/l; serum cortisol greater than 2210 nmol/l; plasma ACTH less than 10 pg/ml; urinary free cortisol 865 nmol/day; estradiol 0.36 nmol/l. Regardless of treatment with antithyroid drugs and an inhibitor of 3 beta-hydroxysteroid dehydrogenase, the patient died of cardiac failure at the age of 4 months. Autopsy findings included a follicle cyst in the right ovary and multinodular hyperplasia in the thyroid and both adrenals. To our knowledge such a severe neonatal form of McCune-Albright syndrome has not been described in the literature.