Aim: Validated instruments exist measuring parts of personal health, ill-health and lifestyle, but there are few, if any, instruments “grasping the big picture” of wellness and ethos. Accordingly the aim was to develop and establish the psychometric properties of a 74-item Ethos towards Wellness Questionnaire (EtWeQ) with regards to content and construct validity, as well as homogeneity and stability reliability. Methods: A questionnaire based on a methodological and developmental design was sent out twice with a four week gap between, on 221 healthy middle-aged participants in four steps: item generating, content validating, statistical analyzing and establishing the final questionnaire. Results: The substantial base, consisting of content validity resulted in, besides basic characteristics, six well-defined and sufficient indexes comprising of; two health indexes (healthiness and ill-healthiness), three life context indexes (work, family, spare time), and one brief comprehensive index (ethos). The three life context as well as the ethos indexes at an ordinal scale level, identified overall satisfactory communalities of >0.30, factor loadings > 0.30, and factor total variance > 50% with regard to construct validity. The homogeneity reliability, in terms of Cronbach’s alpha coefficient > 0.70, at both occasions with a four week gap between, as well as the stability reliability in terms of intraclass correlation coefficient > 0.70, were also considered satisfactory in the same indexes. Conclusions: This newly developed, and likely the only questionnaire focusing on “grasping the big human picture”, was based on both a philosophical reasoning and empirical recommendations of wellness, is shown to be a valid and reliable measurement in screening or in follow-up of healthy people’s wellness and ethos.