Aim: In newly diagnosed carcinoma breast cancer patients, comparing conventional staging and F-18-fluorodeoxyglucose positron-emission tomography-computed tomography (F-18-FDG PET/CT) staging. Materials and Methods: This was a retrospective observational study. A total of 171 new diagnosed carcinoma breast patients who underwent staging F-18-FDG PET/CT scan and routine conventional imaging including mammosonography of breast and axilla, chest X-ray, ultrasound sonography abdomen, and bone scan were included in the study. Staging was done according to the American Joint Committee on Cancer staging (tumor-node-metastasis). Changes in staging and management with F-18-FDG PET/CT scan were assessed. Results: Overall PET/CT upstaged in 22.2% of cases and changed management in 15.78% of cases. PET/CT upstaged in three of eight cases in Stage IA patients but changed management in only one case. In Stage IIA, of 31 patients PET/CT upstaged in two patients (6.45%). In Stage IIB, of 45 patients PET/CT upstaged in six patients (13.3%). In Stage IIIA, of 22 patients PET/CT upstaged in six patients (27.2) and in five patients there is a change in management. In Stage IIIB, of 43 patients PET/CT upstaged in 21 patients (48.8%) with change in management in 13 patients (25.5%). Conclusion: F-18-FDG PET/CT scan can be helpful in upstaging and changing management.