Abstract: Objective To detect the expression level and prognostic value of poly(ADP-ribose) polymerase 1(PARP-1) in oral tongue squamous cell carcinoma(OTSCC),and to analysis the relationship between PARP-1 expression and the clinicopathologic characteristics and prognosis of patients. Methods Expression of PARP-1 in 155 paraffin-embedded specimens of OTSCC and 13 paraffin-embedded specimens of adjacent normal tongue mucosa tissues was detected by the immunohistochemical method.The relationship between PARP-1 expression and the clinicopathologic characteristics and prognosis of patients was analyzed. Results Expression of PARP-1 was observed in 89.0%(138/155) of 155 OTSCC specimens.Overexpression of PARP-1 was observed in 58.1%(90/155) of the 155 OTSCC Paraffin specimens,while low expression of PARP-1 was 41.9%(65/155).Expression of PARP-1 was not observed in 13 normal tongue specimens.There was a significant difference between the 2 groups (χ²=64.815,P=0.000).Expression of PARP-1 positively correlated to T stage(χ²=10.841,P=0.002),N stage (χ²=8.962,P=0.007) and pathological stage (χ²=17.151,P=0.000).The overall survival (P=0.037) and disease free survival (P=0.026) were shorter in patients with overexpression of PARP-1 . Conclusion PARP-1 may play an important role in carcinogenesis and cancer progression of OTSCC.PARP-1 may have a prognostic value in OTSCC.