At the time, this meeting in the Crimea was regarded as a victory for Grand Alliance, but it has become much more controversial since then, and many consider it to be the beginning of the Cold War. Izvestiya went so far as to call the conference "the greatest political event of current times," and The New York Times called the "proposals for the settlement of the Polish question" the "greatest achievement of the conference." This would certainly be disputed later.

Prior to the start of the conference, the Soviet army was posed at the Oder River, awaiting Stalin's command to attack Berlin. Their army was the largest in Europe, with twelve million soldiers, thus both Roosevelt and Churchill were well aware of Stalin's position of power. Churchill had pursued a private meeting with Roosevelt before this, but was evaded for quite some time, just as he had been at Teheran. Eventually the two did get together, but not much was accomplished. During the Yalta Conference Roosevelt seemed fatigued, and two months later he would be dead of a massive cerebral hemorrhage. However, his doctors declared that his health did not affect the decisions he made there.

The agreements reached at Yalta stated that a United Nations conference would be convened on Wednesday, April 25, 1945, in San Fransisco, in order to write themselves a charter. Stalin's bid for one vote per Soviet Republic within the United Nations was brought down to three votes, which was still an unfair advantage.The Big Three also created the Declaration of Liberated Europe, promising political and economic aid for the nations freed after the war, but which had no legal strength. They said that they would promote democratic governments that were chosen by the people through free elections, and that were responsive to all their people. However, Stalin's desire for governments "friendly" to the USSR makes it highly unlikely that he ever intended to allow them sovereignty. Surrender terms for Germany were also decided upon at Yalta, some of which were altered because Churchill would not allow the destruction of their industry. They determined that they would each have authority over one of the four zones that would divide Germany, with the French zone extracted from the American and British zones. Half of the reparations made would be given to the Soviet Union, as they had indeed suffered most from the war. It was concluded that in exchange for the Russians joining the war against Japan several months after the European war was finished, the status quo would be maintained in Outer Mongolia, damages incurred by Russia in the 1904 conflict with Japan would be repaired, and they would receive Sakhalin, the Kurile Islands, and protected interests in the port of Dairen and on various railroads. Basically, Stalin was given at Yalta what he had been promised at Teheran.

Announcing that "The Polish question is a matter of life and death for the Soviet Union," Stalin was greatly preoccupied at Yalta with protecting himself from Germany, and felt that he needed Poland as a buffer, for unlike his allies, he had no body of water surrounding his country. Their negotiations resulted in a provisional government for Poland, with its eastern border for the most part following the Curzon Line. Many of the outcomes of the Yalta conference were due to secret meetings between Roosevelt and Stalin, during which Roosevelt gave in to many of Stalin's demands, and it is likely that Stalin had no intention to keep his side of the deal. The consequence of somewhat superficial and glossy wording regarding the fate of eastern Europe led to the dissolution of the consensus reached. Only a month after the conference, members of the Polish Resistance were taken away by the Soviet government, never to be seen again.

After Yalta, Churchill still seemed to believe that Stalin would keep his word, and Roosevelt announced that he had compromised with regard to the Polish question, but that it was the best possible path for the future of a free Poland. Once Stalin stopped following the Yalta agreements, Churchill wrote to Roosevelt requesting his support in protesting Stalin's actions. He said that they were "in the presence of a great failure and an utter breakdown of what was settled at Yalta." Roosevelt did not respond until three weeks later, when he wrote Stalin a rather weakly worded message of disapproval.

It appears that the Western Allies compromised with Stalin in order to achieve their highest priorities, but that since these were focused on creating a post-war world of stability and peace, they failed in doing so. Instead, their actions welcomed in the Cold War. The question is, was the Cold War unavoidable? It is likely that much worse could have happened without the efforts made by Churchill and Roosevelt. Author Warren Kimball accredits them with this achievement, saying, "Had Churchill and Roosevelt chosen to fight the war solely for post-war advantage against Russia, Communism, and the left, they could not have won the struggle... they could not solve all the political, social, and economic problems of the world, but they could lead their nations to victory and prevent a far worse set of problems. And they did."