Mattering, defined as feeling valued and adding value, is a basic psychological need with significant explanatory power. Although several specific measures have been introduced to assess the construct, no integrated, multidimensional measure exists. This limits the ability of researchers to investigate mattering in ecological contexts. This paper seeks to address this gap by introducing the Mattering in Domains of Life Scale (MIDLS) and evaluating its internal structure and convergent validity. Using data from a single, large US representative sample, the analysis validated the overall hypothesized factor structure, consisting of feeling valued and adding value across the personal, interpersonal, occupational, and community domains, as well as overall mattering. Convergent validity was assessed by comparing the various MIDLS subscales to eight established scales. Overall results provide evidence that the MIDLS is a valid scale measuring an essentially unidimensional construct composed of eight subdomains.