We have investigated the role of high-resolution ultrasound (US) in the analysis of sentinel node(s) in melanoma patients in pre-operative staging and follow-up. One hundred and six lymph node basins in 88 melanoma patients undergoing sentinel node biopsy (SNB) were examined: 25 (23.6%) were US positive for metastases and 81 (76.4%) were negative. Subsequent histological analysis of the 81 negative lymph nodes confirmed the absence of metastases in 80 cases (98.8%), whereas, in the 25 US-positive lymph nodes, metastases were found in 16 cases (64%). The follow-up of all patients submitted to SNB in our unit included a US investigation of operated and contralateral nodal basins every 4 months for the first 3 years and then every 6 months. Of a total of 300 patients, four (1.6%) were found to have locoregional nodal disease during follow-up. In three of these four patients, US was crucial in indicating the presence of nodal metastases, which would have gone undetected on physical examination. The result of this study (negative predictive value of 98.7%) introduces the possibility of selecting patients who may avoid an SNB procedure based on the results of pre-operative US examination.