Sentinel node biopsy is emerging as a successful means of identifying subclinical lymph node disease in mucosal head and neck cancer. Sentinel node studies in melanoma and breast cancer have identified sentinel nodes at unusual sites and the technique is redefining our understanding of dynamic lymphatic flow. In this study, the sentinel nodes in mucosal head and neck malignancies were mapped according to their site within the neck and this was correlated with tumour site within the oral cavity. Fifty-two necks were explored for sentinel nodes from tumours located in the tongue (23 cases), floor of mouth (12 cases), palate (six cases), retromolar trigone (five cases), alveolus (three cases), buccal mucosa (two cases), tonsil (two cases) and lip (one case). In total, 124 sentinel nodes were found in levels I-V. Two hot spots were found in the tonsils and were not excised, two nodes were located in level IIB, four nodes were found in level IV, three in the contralateral neck and one in level V. The sentinel nodes located at unusual sites would not have been excised in a supraomohyoid neck dissection and the study has improved our understanding of dynamic lymph flow from tumours.