Authors develop a new approach to the study of one’s relationships with others, which focuses on the conditions and the effects of the dialogical nature of a person. Theoretical modeling, hermeneutics, qualitative and quantitative methods have been applied. The solution for identifying prerequisites of self-development and social positioning of a person that are rooted in dialogical I-Other relationships has been suggested. The originality of the paper is associated with describing the relation to the other as a reflexive I-Other relationship; with an elaborated model that highlights the variety of dimensions of I-Other relationships (between I and Other, I-in-Other, Other-in-Me, I-in-Myself) results in a truly dialogical mode of being; with revealing the potentials of a Conversation Partner in dialogical I-Other relationships (subjective interrelations and significance of Conversation Partners, their activity, fullness of the reflection of significant Conversation Partners); with a description of different hypostases of Conversation Partners (Real, Ideal, Secret, I as Myself) by the means of hermeneutics. The method called “My Conversation Partner” should also be mentioned, as well as the empirical study of existential and social resources of Conversation Partners. Theoretical background of the study was formed by the works of M.M. Bakhtin, M. Buber, M. Heidegger, J.-P. Sartre. E. Levinas, as well as by the works of modern psychologists such as G.M. Kuchinsky, A.V. Rossokhin, E.B. Starovoytenko, C.T. Brown & P.W. Keller, Hubert Hermans, F. Rivetti Ваrbo, etc. Results of the current research have shown that the potential of social adaptivity, affiliation, dominance, positive solitude, joy of solitude, freedom, self-transcendence, existential fulfillment is associated with the richness of one’s Conversation Partners.