Objectives: This study aimed to investigate the prognostic prediction of germline BRCA1 and BRCA2 mutations by comparing the maximum standardized uptake value (SUV max ) obtained from 18 fluoride-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT), which is considered a prognostic factor in breast cancer (BC). Methods: Retrospective interdisciplinary laboratory results of 92 patients with BC who had germline BRCA1 or BRCA2 mutation profiles and underwent 18 F-FDG PET/CT were compared. Genotyping was made by next-generation sequencing, and PET/CT scans were re-evaluated. The histopathological data, genetic results, and clinical demographics of all patients were recorded. Patients were divided into two groups in accordance with the presence of germline BRCA1 and/or BRCA2 mutations. Between-group statistical comparison was performed. Results: In PET/CT performed for primary staging, patients with BRCA-positive BC had significantly higher SUV max (p=0.039), larger tumor size (p=0.025), and presence of axillary nodal metastases (p=0.023) than patients with BRCA-negative BC. Although the Ki-67 index was higher in the BRCA-positive group than BRCA-negative group, this difference was not significant (p=0.157). Moreover, in the BRCA-positive and negative groups, SUV max , Ki-67 index, and tumor size, grade, and stage were significantly correlated with each other. Conclusion: The results of this study showed a strong association between BRCA mutations and SUV max , which indicates the poor prognosis of BC.