Aim: To analyze bcl-2 protein as marker of regulating apoptosis in periapical tissue reaction which causes bony defects Objective: Immunohistochemical study of periapical lesion gives the clinician a chance to correlate between case history findings and progression of the lesion. Materials and method: Six patients with the history of trauma and having large periapical radiolucency, indicated for periapical curretage were selected. The periapical curretted biopsy specimens were formaline fixed, taken for histopathological and immuno histochemical study. The bcl2 expressions in all specimens were studied. Inference: Bcl2 proteins were positive in all cases, but more in cystic lesions Conclusion: bcl2 proteins were used as markers to understand the extent of the lesion. More bcl2 expressions shows blocked apoptosis, which leads to bony lesions.