Dendritic cells (DCs) are antigen-presenting cells that initiate and modulate immune responses, including tumor immunity. In this study we examined, immunohistochemically, the distribution of DC subsets in the primary tumor, adjacent tissue and regional lymph nodes (RLNs) of patients with oral squamous cell carcinoma (OSCC). The numbers of S100+ and CD1a+ DCs in tissue adjacent to the primary tumor were greater in patients without metastasis to RLNs (PN- cases), compared with those with metastasis (PN+ cases), while greater numbers of CD83+ DCs in the primary tumors were found in PN+ cases. In the RLNs, the numbers of S100+ and CD1a+ DCs were less in PN+ cases than in PN- cases, while the numbers of CD83+ DCs were greater in PN+ cases compared with those in PN- cases. These results suggest that the distribution of DC subsets in OSCC may reflect the degree of tumor immunity induced in the host bearing OSCC.