This article analyzes the construct "Positive Unconditional Regard" proposed by Rogers, one of the three necessary and sufficient conditions for a constructive change a person undergoes as a result of interpersonal exchanges. - The necessary and sufficient conditions of therapeutic personality change (Rogers, 1957) was taken as a main reference in the task of understanding the historical evolution of the construct. As result, it was possible to demonstrate that since 1940 the basic ideas of such concept were present in Rogers' writings, even though he had never employed the expression Positive Unconditional Regard . In fact, it can be shown that his attempts in testing his hypothesis led to the precisely formulation of the construct in the 1957 article. After that period, the construct is employed under different formulations, in different contexts. It will be found as acceptance, esteem and prizing. The applied bibliographical undertake has permitted to draw the historical evolution of the construct, as well as its general configuration.