Cancerous inhibitor of protein phosphatase 2A (CIP2A) has been identified as one of the most commonly altered proteins in humancancers. It blocks the tumor-suppressive action of protein phosphatase 2A (PP2A) complex and enhances malignancy. Thirty-fivepatients with squamous cell carcinoma of the oral cavity underwent surgical resection of the tumor. CIP2A was assessed by quantitativereal-time PCR in the resected tumor tissues and in their adjacent normal tissues. CIP2A was found to be overexpressed inall oral squamous cell carcinoma (OSCC) specimens in comparison to their surrounding normal tissue. CIP2A overexpression wasstatistically correlated with poor prognostic feature of the tumor. Thus, a high expression level of CIP2A was associated with shortersurvival. In conclusion, CIP2A is upregulated in OSCC, and its overexpression is correlated with aggressiveness of the tumor andpoor outcome and survival. It may serve as a prognostic marker of OSCC.