OBJECTIVES: Transthyretin Familial Amyloid Polyneuropathy (TTR-FAP) is a rare, progressive, debilitating and life-threatening neurodegenerative disease. Although a rare disease, Portugal has one of the largest TTR-FAP foci in the world but recent Portuguese epidemiological data is lacking. The purpose of this study was to estimate TTR-FAP prevalence in Portugal. METHODS: TTR-FAP patient’s medicines utilization is fully funded by National Health System in Portugal since 2001. Since March 2013 Portuguese electronic prescription system became more generalized, allowing central monitoring and validation of medicines prescription and dispensing. TTR-FAP anonymized patient’s data was requested to Administração Central do Sistema Saúde (ACSS). The most frequent municipality used for medicines dispensing by each patient was identified and used as a proxy for residence. Portuguese population by municipality was obtained from Instituto Nacional Estatística