OBJECTIVE To determine the parameters supporting the malignancy by comparing demographic features of patients and nodule features in malign and benign nodules according to the pathology results after thyroidectomy in patients with the suspicious fine needle aspiration biopsy (FNAB) results for follicular neoplasia. METHODS Thyroidectomy performed 152 cases with the suspicion of follicular carcinoma owing to the FNAB results were included in the study. Age, radiation exposure history, and serum TSH levels of patients were recorded as well as the ultrasound findings of nodules as nodule count, diameter, internal structure, echogenicity, border features, presence of peripheral halo, and presence of internal micro calcifications. Scintigram findings of nodules were also recorded. RESULTS The mean age of the patients was 48,14 years (range: 20-71 years). Twenty five (16,5%) of the patients were male while 127 (83,5%) were female. Among patients with higher than normal TSH levels, malignancy was more common compared with the patients with normal or lower TSH levels. Presence of intranodular calcifications [Odd's Ratio: 3,1; 95 % Confidence Interval: 1,3-7,4], increase in intranodular vascularization [Odd's Ratio: 14,7; 95% Confidence Interval: 1,4-147,7], absence of halo sign [Odd's Ratio: 0,1; 95% Confidence Interval: 0,04-0,8], and ill-defined margins [Odd's Ratio: 0,1; 95% Confidence Interval: 0,49-0,3] were statistically significantly more common in malignant cases. CONCLUSIONS The ability of clinical features, and sonographic parameters to predict malignancy in indeterminate thyroid nodules should be kept in mind since ultrasound is a simple, easy and inexpensive tool in the diagnosis of thyroid nodules.