To assess the usefulness of ultrasound and ultrasound-guided fine-needle aspiration cytology in detecting occult cervical lymph node metastases, 107 patients with squamous cell carcinoma of the head and neck, who underwent 132 elective neck dissections, had preoperative ultrasound examination. During the assessment of the last 54 patients, who underwent 70 elective neck dissections, ultrasound-guided aspiration cytology was available. Although ultrasound was able to detect lymph node metastases in the majority of patients, the accuracy of this technique never exceeded 70% (93 of 132 procedures). With ultrasound-guided aspiration cytology, accuracy was 89% (62 of 70 procedures). This latter technique seems to be the modality of choice for the assessment of the clinically negative neck. Its use obviates the need for elective neck dissection, done because of the high risk of occult metastasis.