There is a lack of outcome measures to assess the impact of axial spondyloarthritis (axSpA) on health, function and quality of life. The Assessment of SpondyloArthritis International Society (ASAS) group developed the ASAS Health Index (ASAS-HI) and the ASAS Environmental Factors Item Set (ASAS-EF) to measure functioning and health across all aspects of health that are typically affected and relevant for patients with axSpA, based on the International Classification of Functioning, Disability and Health (ICF). The aim of this paper was to describe the translation and cross-cultural adaptation of both questionnaires into European Portuguese among patients with radiographic and non-radiographic axial SpA (nr-axSpA) and test the conceptual equivalence of the translated version in the Portuguese context.The ASAS-HI and ASAS-EF were firstly translated into European Portuguese and then back-translated into English, following forward-backward procedure. After the review of the Portuguese version by an expert committee, the field test with cognitive debriefing involved a sample of 10 axSpA patients with different gender, age, disease duration, and educational background.Minor difficulties arose from the translation process of the ASAS-HI. The EF Item Set offered more difficulties indicating that concepts underlying the contextual factors may be more culture-dependent. A total of 10 patients with axSpA [8 males, mean age of 41.4 (±13.7)] participated in the field test. Cognitive debriefing showed that items of the ASAS-HI and EF Item Set of the Portuguese version are clear, relevant, understandable and easy to complete. As a result of cognitive debriefing, the wording of four items had to be changed to avoid misunderstandings or unintended interpretations, and a new response option "not applicable" was added to two items of the ASAS-HI to improve appropriateness.The resulting Portuguese version of the ASAS-HI and ASAS-EF showed acceptable linguistic validity and has potential for use in both clinical practice and research settings. Nevertheless, before European Portuguese versions can be fully implemented, its psychometric properties (validity and reliability) need to be evaluated.