The paper presents a new model of temperament structure that: (1) is built on the crucial assumptions of the Regulative Theory of Temperament, (2) incorporates the so called temperamental Big Two, (3) and uses the Circumplex of Personality Metatraits to precisely conceptualize the basic temperamental dimensions of Reactivity and Activity. As a result, the new model balancedly differentiates between energetic and temporal aspects of temperamental characteristics both at the conceptual and measurement level. In order to empirically verify the model, a new questionnaire measuring all assumed variables was developed and used together with a set of 10 well-established measures of temperament (including Formal Characteristic of Behavior – Temperament Inventory – Revised) in a sample of 412 participants (55.5% females; M_age = 28.49, SD_age = 11.64). The obtained results support the validity of the new temperament measure, synthesizing potential of the new model, as well as the claim that Reactivity and Activity (in our conceptualization and operationalization) can indeed be treated as fundamental dimensions of temperament, as they turned out to be highly correlated (≈ .80) with two factors extracted from all other temperamental measures used in the study. Theoretical implications and possibilities of the new model are discussed.