Thyroid tumors are rare in childhood and adolescence. A retrospective analysis was done of fifteen patients (8 female) with thyroid carcinoma attended in the Pediatric Endocrinology Unit of the HC-UFPR, from February 1988 to March 2003. The most frequent initial complaint was an anterior cervical nodule. Ten patients were papillary carcinoma (PTC) bearers, four had medullary carcinoma (MTC; three of them with MEN-2B) and one had follicular carcinoma. Two patients with MEN-2B have de novo proto-oncogene RET mutation (Met918Thr). Fine needle aspiration (FNA) was performed in ten patients and was malignancy positive in only five of them. All patients underwent total thyroidectomy. Adjuvant radioiodine (131I) therapy was made in ten patients. Two patients died from unrelated diseases. Nine patients presented no clinical or laboratorial evidence of disease; one (PTC) developed recurrence 5 years after initial treatment and three (1 PTC, 2 MTC) have disease evidence yet. Our prognosis and clinical manifestations data are according to the literature. However, MTC prevalence (27%), sex distribution and FNA results differ from the majority of published casuistics, that can be attributed to the number of cases reported here.