In recent years, diagnostic ultrasound has become established in head and neck surgery. Modern equipment allows high resolution imaging of neck tissue masses, cervical vessels, and lymph nodes. The major advantage of B-mode sonography is its ability to detect neoplasms in solid scarred neck tissue, commonly seen in patients with radical neck surgery. Postoperative or radiogenic edema, tumor recurrence, and lymph node involvement can be differentiated. Inflammatory and neoplastic lymph node diseases detected by echography must be differentiated by biopsy. Tumor recurrence was seen in 21 of 152 patients by echography. Twelve patients were diagnosed by clinical examination and 17 were diagnosed by computed tomography. Two false positive and one false negative sonographic diagnoses were made. B-mode sonography is an important instrument in the follow-up examination of head and neck tumors for early detection of tumor recurrence or tumor persistence.