Introduction: Evaluating the impact of surgical treatment on health-related quality of life of breast cancer patients has become increasingly relevant, particularly for reconstructive procedures. The BREAST-Q consists of a broadly used patient-reported outcome measure to assess the impact of breast surgery on the health-related quality of life of these patients. The aim of this study was to translate and linguistically validate the BREAST-Q reconstructive module to European Portuguese.Material and Methods: The translation and linguistic validation process was based on the International Society for Pharmacoeconomics and Outcomes Research guidelines and started after obtaining permission from the original authors (developers). It involved two direct English to European Portuguese translations and a back translation, maintaining conceptual and cultural equivalence, an expert panel discussion, cognitive interviews with five patients and a final consensus.Results: The forward translations led to the revision of three conceptually distinct items. The backward translation resulted in predominantly wording discrepancies and the three conceptual disparities noted in the back translation were revised on a consensual version. All material was openly discussed with the original authors and in an expert panel meeting. One item was changed after the cognitive interviews. The final consensual version was obtained.Conclusion: This stepwise approach allowed to linguistically validate the BREAST-Q reconstructive module to European Portuguese so that it can be used in the Portuguese population. Additionally, the applied methodology may serve to support and guide other instruments for linguistic validation.