The thyroid specialist frequently evaluates thyroid nodules because they may represent malignancy. Nodules are typically found on physical examination or incidentally when other imaging studies are performed. Malignant or symptomatic nodules that compress nearby structures warrant surgical excision. Yet, the majority of thyroid nodules are asymptomatic and benign, so the thyroid surgeon must rely on diagnostic studies to determine when surgery is indicated. Ultrasound is the preferred imaging modality for thyroid nodules, and the ultrasound guided fine-needle aspiration biopsy (FNAB) is the preferred method of tissue sampling. Nodules 1 cm or larger or nodules with suspicious sonographic appearance warrant cytologic analysis to better quantify the risk for malignancy. Molecular biomarkers are a powerful adjunct to cytology. Detecting malignancy preoperatively allows total thyroidectomy in a single operation without the need for frozen section or a second operation for completion of a thyroidectomy if malignancy is found during the initial thyroid lobectomy.