: Cushing syndrome due to ectopic secretion of ACTH in infants is rare. The treatment of choice is radical resection of the tumour in combination with pre-operative chemotherapy using steroidogenesis inhibitors if necessary. If radical surgery is not possible, palliative treatment of hypercortisolemia is recommended. The most frequently used drug in infants is ketoconazole. Experience with the use of metyrapone is poor. We report an 8-month-old female infant with congenital immature sacrococcygeal teratoma secreting AFP, beta hCG and ACTH who had undergone non-radical resection of the tumour mass and was receiving standard risk chemotherapy (vinblastine, bleomycin, and cisplatin). The infant initially presented at the age of 6 months with ACTH-dependent Cushing syndrome (cortisol and ACTH level 325 ng/mL, 112 pg/mL respectively). Treatment with ketoconazole was initiated with a dose of 600 mg/day. Due to its ineffectiveness metyrapne was added in increasing dosages, up to 1,500 mg/day. In addition the schema of chemotherapy was changed (adriamycin, bleomycin, carboplatin), which resulted in normalization of cortisol levels and blood pressure. There were no metyrapone side effects during the treatment period. We can conclude that treatment with metyrapone at a dose of 1500 mg/day might be effective and safe in infants with Cushing syndrome.