The paper presents a new Russian-language instrument measuring existential fulfillment within the theory of 4 existential fundamental motivations developed by A. Längle. Based on phenomenological descriptions of the constructs and expert discussions, we developed an original Russian-language set of 94 items, which was validated in 2 online samples (N=818 and N=215). Using hierarchical cluster analysis and confirmatory factor analysis with cross-validation in an independent sample, we arrived at a set of 36 items grouped into 4 scales and 12 subscales (corresponding to theoretical prerequisites of fundamental motivations). The scales demonstrate acceptable reliability (α in the .79-.88 range, .93 for the general score). We sought evidence of convergent and discriminant validity of the scales by using correlational and multiple regression analyses of their associations with indicators of emotional, social, and psychological well-being, subjective happiness, satisfaction with life, basic psychological need satisfaction, self-esteem, internal locus of control, as well as alienation and psychopathology. The findings support the convergent validity of existential fulfillment indicators against well-being measures based on different theoretical approaches, as well as discriminant validity of specific existential fundamental motivation scales. The new instrument opens up new possibilities for empirical research in the field of existential psychology and, in a broader context, the psychology of self-actualization, well-being, and life satisfaction. The questionnaire can also be used in assessment, counseling, and psychotherapy.