The frequency of neck metastasis in lip cancer patients is low, however if present, it decreases survival rates, which reinforce the neck treatment as an important step in the management of these patients. This study evaluates the predictive factors, the distribution of lymph node metastasis and their implications on the neck treatment. A retrospective analysis of lip cancer patients treated in our institution from 1969 to 1999 was performed. A total of 617 patients were analysed. One hundred and seven patients (17.3%) were submitted to a neck dissection. T3/T4 tumours and commissure involvement were significantly associated with the risk of neck metastasis (P<0.001 and P=0.004, respectively). No cases had levels IV and V involved with node metastasis, either clinically or pathologically. The results suggest that supraomohyoid neck dissection could be the option for the elective treatment in T3/T4 tumours and those with commissure involvement, and the therapeutic option for patients with clinically positive necks.