A 49-year-old man with history of nodular goitre operation was referred to our clinic because of MTC in postoperative pathology. He had hypertension, postoperative hypothyroidism, no family history of thyroid carcinoma and sudden death. Laboratuary investigations showed high level of calcitonin (C) (763 pg/ml; normal<150), Carcino embryogenic antigen (CEA) (175 ng/ml; normal<2.5), normal thyroid function tests, parathormone, urinary catecholamines. Ser904 polymorphism in exon15 of RET protooncogen was found. When the postoperative pathologic preperations were reevaluated, immunohistochemical stainings resulted in positivity of C and chromogranin. The postoperative thyroid ultrasonography (TUSG) demonstrated residual tissue with dimensions of 34×27 mm on right, 23×18 mm on left side, multiple lymph nodes (LN) up to 2 cm in diameter at neck regions. He underwent complementary thyroidectomy and neck exploration. Thyroid residual tissue wasnt seen, established LN were excised during operation. Postoperative pathology revealed metastasis of MTC, TUSG demonstrated residual tissue and C raised to 1146. After 2 months, modified neck disection and complementary thyroidectomy were performed. Tissue at the left thyroid region and bilateral detectable LN were resected. The pathologic examination of LN was positive for MTC. At postoperative first month, C was 1896. Residual tissue dimensions were measured as 4×3 cm on the left, 2×1 cm on the right side, and 2×1 cm at the isthmus during TUSG. Radiotherapy was performed to neck and thyroid region. After two months, C was high, at 850. Meanwhile; heterogen, hypodense, nodular lesion which extended to retrosternal region and had semisolid, cystic components was determined at tomography Whole body imaging with I-131 MIBG and 18 FDG PET were normal. Nadir value of C and CEA were determined as 253, 18.4 respectively at postradiotherapy period, but C levels reincreased later. FNA was performed from thyroid tissue with dimensions of 20×16 mm. Its pathology was consistent with metastasis of MTC. He was operated for fourth time. Despite there was no residual tissue at postoperative thyroid screening, C and CEA levels increased to 385 and 15.77, subsequently. We present this case to state difficulties in management of MTC. He and his first degree relatives have been followed up at our clinic.