Objective: Perineural invasion (PNI) in oral squamous cell carcinoma (SCC) is recognized as a significant predictor of outcome. Perineural invasion is associated with locoregional recurrence and decreased survival of patients with head and neck squamous cell carcinoma, independent of other factors. Nerve growth factor (NGF) may play a role in PNI in several malignancies such as breast, prostate, and pancreatic cancers. We investigated the hypothesis that NGF may be present or highly expressed in oral squamous cell carcinoma with histological evidence of PNI but not in those without PNI.