The immunohistochemical method was applied to show Bak expression in oral squamous cell carcinoma and its metastases to lymph nodes (LNMs). Bak expression was evaluated by immunohistochemical methods in specimens with oral squamous cell carcinomas and their lymph node metastases. Immunohistochemical studies were performed, using goat polyclonal Bak antibodies (Santa Cruz Biotechnology, USA) at 1:200 dilution. Our studies revealed over expression (64%) of Bak in the cytoplasm of epithelial cells in primary tumours (PTs) and in (75%) LNMs. No statistically significant correlations were observed between Bak immunoreactivity and age, pT and G of the carcinoma in PTs and LNMs. We conclude that expression of Bak may be useful for better characterising and predicting the prognosis of OSCC but cooperative studies are needed to assess its applications in the clinical practice.