Background. Toxic goiter describes the goiter that is associated with hyperthyroidism (hyperproduction of thyroid hormones) which relates to diffuse toxic goiter (Grave’s disease) and toxic multinodular goiter. The main signs of hyperthyroidism are: unintentional weight loss, tachycardia, palpitations, tremor, nervousness, anxiety, irritability, increased sensitivity to heat, fatigue. Recent studies suggest a higher risk of cancer (10-20%) in toxic goiter that increase the concern about the diagnosis and treatment of these patients. Case report. A 38 years old male patient was admitted to Department of general surgery with complaints of globe sensation in the neck, presence of a lump in the anterior cervical region, trembling, palpitations, weight loss (≈25 kg in 3 mounths), fatigue and general weakness which appeared 5 years ago and limited patient`s daily activities. The presumptive diagnosis was toxic diffuse goiter IV degree, thyrotoxicosis grave form, thyrotoxic heart disease and ophthalmopathy class III. He followed multiple treatments at the endocrinologist, but the patient's state did not improve afterward. Hereditary background registered that his mother had hemithyroidectomy. Clinical examination: a lump in the anterior cervical region with tenderness and pain at the palpation, exophthalmia and tachycardia (100 beats per minute). Laboratory data: T3 ↑ - 12,28 nmol/L, T4 ↑ - 264,67 nmol/L, TSH↓ - 0,001uIU/mL, Calcitonin ↑ - 52 pg/mL. The ultrasound revealed hypoechogenity of the thyroid and its dishomogeneous structure, increased vascularization of the thyroid tissue ``thyroid inferno``, regional lymph nodes of normal size. After five days of preoperative medication with antithyroid agents, betablockers and desensitizing drugs the pacient underwent surgical intervention. Under general anaesthesia it was performed total thyroidectomy according to the result of extemporaneous hystological investigation of right lobe – follicular-pappilar carcinoma. Definitive hystological investigation confirmed follicular-pappilar multinodular carcinoma of the thyroid. The postoperative period evolved favorably with the patient`s recovery and his discharge on the sixth postoperative day without any particularities. Conclusions. Younger age, male sex and hyperthyroidism are associated with higher risk of thyroid cancer. The patients with toxic goiter must be carefully evaluated regarding risk factors, history, and clinically suspicious signs of malignancy. Rather than antithyroid therapy, surgery is the treatment of choice in toxic goiter, furthermore in toxic goiter associated with thyroid cancer.