BACKGROUND: When the initial root canal treatment fails, retreatment is often considered. The decision of retreatment depends upon factors like the type and location of affected root canal, anatomical complexities and severity of disease, which need to be assessed accurately. Cone Beam Computed Tomography (CBCT) can provide supplementary information which a two dimensional image may fail to provide. The aim of this study was to compare Intra–Oral Periapical (IOPA) Radiographs and limited Cone Beam Computed Tomography (CBCT) in evaluation of teeth undergoing re–root canal treatment. MATERIALS AND METHODS: 50 (118 roots) symptomatic endodontically treated molars were assessed using IOPA radiographs and CBCT images for missed canals, adequacy of root canal fillings (under filling, overfilling and homogeneity of root canal filling), procedure errors (ledges) and persistent periapical lesions. RESULTS: Among 50 teeth (118 roots) IOPA radiographs identified 129 root canals whereas CBCT identified 165 root canals. CBCT detected additional 11 missed canals in 9 teeth (73.3%), 27 underfilled (33.3%) and 45 non–homogenously filled canals (45.8%) when compared to IOPA radiographs which was statistically significant. IOPA radiographs overestimated overfilling when compared to CBCT by 18.2%. IOPA radiographs identified abscess in 20 teeth and cyst in 1 tooth whereas CBCT images detected abscess in 27 teeth and cyst in 3 teeth however these differences were statistically insignificant. CONCLUSION: CBCT is a promising diagnostic modality which provides the clinician with detailed information about the missed canals, adequacy of root canal fillings and periapical lesions in initially failed root canal treated molars. This additional information can influence the clinicians approach towards treatment planning and increase the success of re–root canal treatment.