Objective: Adrenocortical tumors are rare childhood neoplasms. More than 95% are functional and present with virilization, Cushing’s syndrome, hypertension, or hyperestrogenism. The objective of this paper is to present the clinical, laboratory and pathological findings of this rare disease and to highlight the secretory behavior of these tumors.Methods: Clinical and laboratory data of seven Iranian children and adolescents aged between 2 and 16 years with functioning adrenocortical tumors are presented. Five patients had virilization and two had Cushing’s syndrome at the time of diagnosis. In all subjects, the tumors were removed successfully by open surgery, during which a blood sample was drawn from the corresponding adrenal vein for hormonal evaluation.Results: Peripheral blood evaluation revealed that in addition to the dominant hormone (testosterone in the cases presenting with virilization and cortisol in those with Cushing’s syndrome), significant amounts of other hormones were secreted from these tumors. Adrenal vein evaluation revealed that testosterone, dehydroepiandrosterone sulfate, estradiol, ?17(OH) progesterone, and cortisol were directly released from the tumor. The tumors weighed between 36-103 grams. The patients have since been followed for 5 to 20 years, and there have been no signs or symptoms of relapse in any of the patients.Conclusions: The study shows that functioning adrenocortical tumors should be considered in children and adolescents presenting with hyperandrogenism, Cushing’s syndrome, or hyperestrogenism. A diagnosis of a functioning adrenocortical tumor requires surgical removal as early as possible to prevent the untoward effects of virilization or corticosteroid excess. Evaluation of adrenal vein hormones showed that the steroids are secreted directly from the tumor and peripheral conversion has little contribution to the serum levels.Conflict of interest:None declared.