The incidence of endocrine carcinomas is about 5.3 persons per 100,000 population. Most frequent are malignancies of the thyroid gland (about 89%).Because of low incidences and missing prospective studies as well as radiotherapy and chemotherapy resistance, general accepted therapy guidelines for endocrine carcinomas are still missing. Surgery and radionucleotide treatment is generally the first-line therapy. Hormonal active carcinomas can be additionally treated with special substances such as octreotide and mitotane. Chemotherapy is frequently not effective. Widely used substances are cyclophosphamide, cisplatin, doxorubicine, dacarbazine, vincristine and etoposide. This first part of the review will present medical therapies of thyroid carcinomas, adrenal carcinomas and parathyroid carcinomas. The second part in one of the next issues will focus on less frequent endocrine carcinomas of the gastrointestinal tract.