Abstract: This study want to determine correlation of cyclooxygenans 2 (Cox-2) expression and inflammatory reaction in colorectal carcinoma. Archival H and E slides of 150 patients with primary colorectal carcinoma were reviewed to confirm pathological feature and to select suitable tissue blocks for immunohistochemical staining with mouse monoclonal antibody against human Cox-2 and various inflammatory cells. After scoring, statistical analysis were carried out with SPSS software, χ2 methods and bivariate pearson correlation analysis. The expression of Cox-2 (grade 3 to 7) in 71.3% of patients associated with mast cells, neutrophils, eosinophils, macrophages, CD3+ lymphocytes infiltration was significant (p = 0.001). Correlation of Cox-2 expression associated with CD8+ lymphocytes infiltration was not significant (p = 0.569). Also CD3+ lymphocytes show severe infliltration when the expression of Cox-2 is negative (p<0.05). The main purpose of this study was to evaluate the interaction between the Cox-2 expression and inflammatory cells infiltration. This study showed that there is a close relationship of Cox-2 expression and mast cells, neutrophils, eosinophils, macrophages and CD3+ lymphocytes. The only exception was CD8+ lymphocytes. It is may be due to independent role of anti tumoral effect of this inflammatory cells.