What is vitality and how can it be measured? The core dimensions of vitality and the Dutch Vitality Questionnaire Background Policymakers, professionals and researchers increasingly use vitality as a health-related concept. Although there are various definitions of vitality, consensus is lacking, just as instruments measuring it. Therefore, TNO and RIVM started a study aiming to describe vitality and developed an instrument (the Vita-16) to measure vitality among the Dutch adult population. Method Vitality was described based on (scientific) literature and expert opinions. Subsequently, the measurement instrument (the Vita-16) was developed. Step 1 involved selecting items from existing questionnaire measuring vitality. During step 2, policymakers, professionals and researchers scored these items on relevance. Based on consensus rules relevant items were selected and combined into a concept vitality questionnaire, which was pilot tested (step 3) to gain insight into comprehensiveness and ceiling effects. During step 4 (validation study), the concept vitality questionnaire was online tested among 1300 Dutch. Items were reduced based on collected data and the final questionnaire was validated by verifying the structural and construct validity. Results Vitality consists of three core dimensions, namely: Energy, Motivation and Resilience in which energy is characterized by feeling energized and full of pep, motivation by setting goals in life and putting effort into achieving these goals, and resiliency by the ability to cope with daily life problems and challenges. The distinction between vitality, determinants and outcomes has led to a conceptual model of vitality. The three core dimensions can be measured using a 16-item questionnaire, which appeared to be reliable (a:0.89-0.95) and has showed good validity. Conclusion The concept of vitality is differentiated in three core dimensions, which can be measured in the Dutch adult population using a validated 16-item questionnaire (the Vita-16).