Lymphatic metastasis of oral squamous cell carcinoma (SCC) is important for prognosis and clinical decision making concerning the treatment of the neck but may be difficult to detect. Activated leukocyte cell adhesion molecule (ALCAM), has been shown to correlate with prognosis or tumor grade in different tumor types and may be a predictor of lymphatic metastasis. ALCAM expression at the invasive front in fresh frozen tissue samples of oral SCC's (n=41) was studied immunohistochemically, using a polyclonal antibody directed against ALCAM's extracellular domain. Membranous expression of ALCAM at the invasive front was significantly related to lymph node metastasis (p=0.001, sensitivity 69%, specificity 84%) and tumor grade (p=0.035). There was no significant relationship with tumor thickness (p=0.394). Lymph node status (p=0.030), correlated with 5-year overall survival. A significant relation between ALCAM and prognosis could not be established, due to an insufficient sample size. However, ALCAM expression does appears to increase risk of early death. Membranous ALCAM expression at the invasive front serves as a molecular marker for lymphatic metastasis and may facilitate better treatment choices concerning the neck in patients with oral SCC.