Objective: The aim of the present study was to investigate the role of inflammation in angiogenesis of keratocystic odontogenic tumor (KCOT). Study Design: Twenty inflamed and 20 non-inflamed KCOTs were selected based on quantitative scoring of inflam mation which was also applied on 20 radicular cysts. Microvessel density was assessed in all samples using CD34 antibody and angiogenesis was compared between the three groups. Statistical analysis was performed using one- way analysis of variance followed by post-hoc Scheffe test and P values less than 0.05 were considered significant. Results: A statistically significant difference in angiogenesis was found between radicular cysts and both inflamed and non-inflamed KCOTs (P < 0.001), but not between inflamed and non-inflamed KCOTs (P =0.347). Conclusion: Based on the results obtained in the present study, it seems that the effect of inflammation on angio genesis in KCOT is minimal. However further investigation using other methods of evaluation is suggested to fully clarify the role of "inflammatory angiogenesis" in this neoplasm.