The aim of the present paper was to study some characteristics and possibility of surgery of anaplastic thyroid cancer. During five years period in Center for endocrine surgery, we found anaplastic thyroid cancer in 65 patient (44 female and 21 male), median age 63 years (from 37 to 88 years). Surgical treatment was peerformed in one half (32) anaplastic thyroid cancer patients, at majority of them operative biopsy or tumor reduction only. Radical surgery was performed in about 10% patients. Possibility of surgery in anaplastic thyroid cancer are very limited. In one third patients there were long standing goiter or thyroid nodule or histological verified dedifferentiation of papillary thyroid cancer. This patient should be operated formerly, before anaplastic transformation.