Ruwaida Ramadan Ali Mira¹, Nadia Abbas I. El-Sissy², Mohamed I. Mourad³, Mona Younis Youssef Abd Allah4 BDS, Faculty of Dentistry, Alzawia University, Libya. Professor of Oral Pathology Faculty of Dentistry Mansoura University.  Assistant professor of Oral Pathology Faculty of Dentistry Mansoura University. Mona Younis Youssef Abd Allah Abstract: Squamous cell carcinomas (SCC) comprise of more than 90% of oral cancers arising in the mucous Membranes of the oral cavity and oropharynx [1  This present study aimed to assess the possible relation between carbonic anhydrase (CA-IX) as hypoxic marker and proliferating cell nuclear antigen (PCNA) as proliferating marker immunoreactivities and their possible roles in tumorogenesis among the current study OSCC cases. Materials and Methods: the study groups included 40 cases of OSCC. Were examined by immunohistochemical staining (CA-IX, PCNA). Pathological data were statistically analyzed to detect the possible statistical significant differences and correlations between the different variables. Results: Adirect statisticallysignificance was observed between CAIX expression with tumor size and histological grad. In addition a Direct statisticallysignificance was noticed between PCNA expression and histological grads. Conclusion: - these data showed that the combination of the expression of CAIX and PCNA might provide a useful prognostic marker in oral squamous cell carcinoma.