The presented text depicts the final stage in the attempts made in Bulgarian policies aimed at the realisation of a South Slavonic federation. This conception waned directly after the Soviet-Yugoslav-Bulgarian meeting held at the Kremlin on 10 February 1948. After analysing the motives for the call to come to Moscow, made to the leaders of Yugoslavia and Bulgaria by Stalin in order to admonish them for 'license' and to render them dependent upon the Soviet Union, the author went on to outline the course of the Kremlin debate, composed mainly of the charges and grudges formulated by the Soviet leader and addressed to the representatives of the highest authorities of both south Slavonic states.The outcome of agreements imposed on the Bulgarian and Yugoslavian delegations and dealing with the future 'consultations' by Sofia and Belgrade of all important decisions pertaining to international affairs, together with the tactical move made by the Soviet dictator and involving the immediate creation of a Bulgarian-Yugoslav federation under Soviet control, proved to be totally different in the policies of each of the two states. Already at the beginning of March 1948 the party-government authorities of Yugoslavia unanimously rejected the planned union with Bulgaria. They did so particularly in view of the fact that at the time of the already open conflict between Belgrade and Moscow, the Bulgarian leaders openly supported the Soviet stand. On the other hand, the rulers in Sofia continued to accentuate the urgent need for a state union between Bulgaria and Yugoslavia; they declared, however, that this step should be made after the 'Tito clique' was toppled by the 'wholesome forces within the Communist Party of Yugoslavia' and the appointment of new Yugoslav authorities, compliant to the Soviet Union. At the same time, Sofia continued the Macedonianisation of the Pirin Region despite the split between Yugoslavia and the Soviet bloc. Nevertheless, within the Yugoslav Federation, the People's Republic of Macedonia was no longer to act the part of Piedmont in the unification of the Pirin, Aegean and Vardar Macedonians; this function was now fulfilled by Pirin Macedonia in the People's Republic of Bulgaria. As the Yugoslavian-Soviet conflict grew more intense, international relations upon the Sofia -Belgrade line deteriorated, and in fact were broken at the end of that year. This development signified a definite decline of the very notion of a south Slavonic federation.