On 19 November 1942, the Red Army launched Operation Uranus. The attacking Soviet units under the command of Gen. Nikolay Vatutin consisted of three armies. This included a total of 18 infantry divisions, eight tank brigades, two motorized brigades, six cavalry divisions and one anti-tank brigade. The Soviets pushed past the Romanian Third Army. The response by the "Wehrmacht" was disorganized. Bad weather prevented air attacks against the Soviets.
On 20 November, a second Soviet offensive (two armies) was launched to the south of Stalingrad against the Romanian 4th Army Corps. The Romanians were overrun by large numbers of tanks. The Soviet forces moved west and made a ring around Stalingrad.
About 265,000 German, Romanian, Italian soldiers, the 369th (Croatian) Reinforced Infantry Regiment, and other troops including 40,000 Soviet volunteers fighting for the Germans. were surrounded. There were 210,000 Germans on 19 November 1942. There were also around 10,000 Soviet civilians and several thousand Soviet soldiers the Germans had taken captive during the battle. Not all of the 6th Army was trapped; 50,000 were not surrounded. Of the 210,000 Germans surrounded, 10,000 remained to fight, 105,000 surrendered, 35,000 left by air and the remaining 60,000 died.
The Red Army formed two defensive groups. Field Marshal Erich von Manstein told Hitler not to order the 6th Army to break out. Manstein thought that he could break through the Soviet troops and free the 6th Army. After 1945, Manstein says he told Hitler that the 6th Army must break out. The American historian Gerhard Weinberg said that Manstein lied.
Manstein was told to attack Stalingrad in Operation Winter Storm ("Unternehmen Wintergewitter"). He thought that this attack could work if the 6th Army was supplied through the air.
Adolf Hitler had said on 30 September 1942 that the German army would never leave the city. At a meeting shortly after the Soviets formed a ring around the Germans, the German army chiefs wanted to try to escape to the west of the Don. Hitler thought that the Luftwaffe could supply the 6th Army with an "air bridge". This would allow the Germans in the city to fight while a new force was assembled. A similar plan had been used a year earlier at the Demyansk Pocket.
The director of "Luftflotte" 4, Wolfram von Richthofen, tried to get this decision stopped. The forces under 6th Army were almost twice as large as a regular German army unit, plus there was also a corps of the 4th Panzer Army trapped in the city. The maximum they could deliver a day was far less than the minimum needed.
To add to the limited number of Junkers Ju 52 planes the Germans used other planes like the Heinkel He 177 . General Richthofen told Manstein on 27 November that the Luftwaffe could not supply 300 tons a day by air. Manstein now saw the problems of a supply by air. The next day he made a report which said that the supply by air would be impossible. He said the Sixth Army should try to escape. He said that giving up Stalingrad would be a difficult loss, but that it would keep the Sixth Army intact. Hitler said that the Sixth Army would have to stay at Stalingrad and that the air force would supply it until the Germans could attack the Soviets.
The "Luftwaffe" was able to deliver an average of of supplies per day. The most successful day, 19 December, delivered of supplies in 154 flights. In the early parts of the operation, more fuel was shipped than food and ammunition because the Germans thought they could escape from the city. Transport airplanes also flew out sick or wounded men from the city. The German attack did not reach the 6th Army. The air supply operation continued. The 6th Army slowly starved. 160 German transport aircraft were destroyed and 328 were heavily damaged. Some 266 Junkers Ju 52s were destroyed.
Soviet forces grouped together around Stalingrad. Violent fighting to attack the Germans began. Operation Winter Storm ("Operation Wintergewitter"), the German attempt to rescue the trapped army from the south, was at first successful. By 19 December, the German Army had pushed to within 48 km (30 mi) of Sixth Army's positions. Some German officers asked Paulus go against Hitler's orders and try to escape out of the Stalingrad. Paulus refused. On 23 December, Manstein's forces had to defend themselves from new Soviet attacks.
On 16 December, the Soviets launched Operation Little Saturn. It attempted to make a hole through the Axis army (mainly Italians) on the Don and capture Rostov. The Germans set up a defence of small units. 15 Soviet divisions—supported by at least 100 tanks—attacked the Italian Cosseria and Ravenna Divisions. The Soviets never got close to Rostov because of the Italian defence.
The German attempt to break through to Stalingrad was stopped and Army Group A was told to come back from the Caucasus.
The 6th Army could no longer hope to escape. The 6th Army did not have enough fuel. As well, the German soldiers have found it very hard to break through the Soviet lines on foot in the cold winter conditions.
The Germans retreated from the suburbs of Stalingrad to the city itself. The loss of the two airfields, at Pitomnik on 16 January 1943 and Gumrak on the night of 21/22 January, meant an end to air supplies and to the flying out the wounded. The third and last runway was at the Stalingradskaja flight school, which had the last landings and takeoffs on the night of 22–23 January. After that, there were no landings except for air drops of ammunition and food.
The Germans were now not only starving, but running out of ammunition. They continued to fight because they thought the Soviets would execute any Germans who surrendered. A Soviet group (Major Aleksandr Smyslov, Captain Nikolay Dyatlenko and a trumpeter) carried an offer to Paulus: if he surrendered within 24 hours, he would receive a guarantee of safety for all prisoners, medical care for the sick and wounded, prisoners allowed to keep their personal belongings, food rations, and be sent to any country they wanted after the war. Paulus was ordered not to surrender by Hitler, so he did not respond.
On 30 January 1943, the 10th anniversary of Hitler coming to power, Goebbels said "The heroic struggle of our soldiers on the Volga should be a warning for everybody..." Also on that day Hitler promoted Paulus to "Generalfeldmarschall". Since no German Field Marshal had ever been taken prisoner, Hitler assumed that Paulus would fight on or kill himself.
The next day, the southern group in Stalingrad was defeated by the Soviets. Soviet forces reached the entrance to the German headquarters. General Schmidt surrendered the headquarters. Paulus said he had not surrendered and refused to order the remaining German forces to surrender.
Four Soviet armies attacked the remaining northern group. On 2 February, General Strecker surrendered. Around 91,000 tired, ill, wounded, and starving prisoners were taken, including 3,000 Romanians (the survivors of the 20th Infantry Division, 1st Cavalry Division and "Col. Voicu" Detachment). The prisoners included 22 generals. Hitler was angry and said that Paulus should have killed himself, but instead "he prefers to go to Moscow." Paulus was Roman Catholic and therefore did not.
The German public was not officially told of the loss until the end of January 1943, though positive media reports had stopped in the weeks before the announcement. Stalingrad marked the first time that the Nazi government publicly admitted a failure in its war effort. It was a major defeat where German losses were almost equal to those of the Soviets. Prior losses of the Soviet Union were generally three times as high as the German ones. On 31 January, German state radio played the Adagio movement from Anton Bruckner's Seventh Symphony, followed by the announcement of the defeat at Stalingrad.