Galectin-1 (Gal-1) is a newly found immunoregulatory carbohydrate-binding protein in cancer biology. The purpose of this study was to evaluate the effects of Gal-1 on oral squamous cell carcinoma (OSCC) development. Immunohistochemistry, Western blotting and RT-PCR were carried out in 62 primary OSCC, 38 oral leukoplakia (OPL) tissues to detect the Gal-1 expression in both protein and mRNA levels. Ten normal oral mucosa (NOM) tissues were used as control. Gal-1 protein was significantly overexpressed in OSCC cancer cells and OPL prickle cells compared to NOM (P<0.05). In accordance with Gal-1 protein, Gal-1 mRNA was also up-regulated in OSCC tissues and OPL tissues. Furthermore, both the Gal-1 protein and mRNA in OSCC tissues were higher than in OPL tissues (P<0.05). Our data supports the important roles of Gal-1 in OSCC development and suggests that Gal-1 upregulation in the OSCC and OPL tissues might be a predictor of early oral carcinogenesis.