An important diagnostic tool for the evaluation of thyroid disease, thyroid ultrasound has recently become available for use in surgical offices. The purpose of this report is to determine the lesional sensitivity of office-based thyroid ultrasound and its impact on clinical decision making. Surgical office-based thyroid ultrasound was performed on 49 consecutive patients who presented with thyroid disease. Indications for sonography included a solitary palpable nodule (n = 32), multiple palpable nodules (n = 3), diffuse enlargement (n = 5), or other hormonal or radiologic abnormalities (n = 9). Thyroid ultrasound demonstrated 104 lesions compared with 38 lesions found on physical examination (P 0.0001). In the subpopulation who underwent scintigraphy (n = 10), 24 nodules were identified by ultrasound and only 10 nodules were identified by scan (P 0.01). Overall, office-based thyroid ultrasound impacted the clinical management of 40 patients (80%): in 16 patients, thyroid ultrasound was the only modality that demonstrated a multi-nodular condition, thus contributing to a decision to avoid surgery; 19 patients had ultrasound-guided fine-needle aspiration of vaguely palpable or nonpalpable lesions; and 5 patients underwent ultrasound-guided cyst aspiration and follow-up. Office-based thyroid ultrasound performed by surgeons is a highly accurate imaging modality that identified significantly more lesions than physical examination or scintigraphy. Clinical management was affected through the identification of a multinodular process or through facilitation of accurate image-guided biopsy. The evaluation of thyroid disease continues to change with recent advances in thyroid imaging and cytological analysis. Ultrasound was first used to study the thyroid gland in 1967, primarily to distinguish solid lesions from cystic lesions (1). In 1987, Rizzatto discussed the use of ultrasound-guided fine-needle aspiration (FNA) biopsy for diagnosing thyroid nodules (2). Hatada reported a higher accuracy (68%) and lower inadequate sample rate (17%) for ultrasound-guided FNA compared with standard FNA (accuracy, 48%; inadequate sample, 30%) (3). Ultrasound has become the primary imaging modality in the assessment of thyroid disease and has proven to be especially useful in identifying patients with a solitary nodule. In a recent study, Brander demonstrated that 31% of patients with a single thyroid mass on physical examination have a multinodular process on ultrasound (4). A multinodular process demonstrated by ultrasound suggests a benign process and allows for nonoperative management, especially when supported by benign cytology.