background: Positive orientation (PO) is a hidden variable explaining a tendency to formulate global evaluations regarding one's self, life and the future. It is inherited to a large degree and it could be considered a common base for numerous aspects of subjective well-being. The self-concept, in turn, is a basic adaptation formed during individual experiences that is responsible for adjustment. The primary aim of the current study was to verify hypotheses about the significant relationship between PO and a "core self" (high self-concept clarity, low self-esteem contingency, low self-rumination), as well as the meditational role of the "core self" in the relation between PO and hedonic balance. participants and procedure: A group of 200 participants completed several measures referring to PO, self-concept and emotions. results: The canonical correlation analysis revealed PO to be a strong predictor of the adaptive features of the self-concept. Moreover, the tested models suggest that (1) self-concept clarity is a significant mediator between PO and hedonic balance, and (2) PO directly predicts only self-concept clarity, whereas its relations with self-esteem contingency and rumination are mediated by the self-knowledge structure. conclusions: These findings indicate that PO is an important and independent factor enhancing adaptive features of the self-concept structure as well as well-being. [ABSTRACT FROM AUTHOR]