Initially, the 3rd Army, which was subordinated to the German 17th Army, consisted of the Cavalry Corps (5th, 6th and 9th Cavalry Divisions) and the 1st Corps (2nd Mountain Division and German 298th Infantry Division). It also had 3 observation squadrons assigned to it. However, after reorganization, on 7 August, it remained only with Cavalry Corps.

On 4 August, the 5th Cavalry Division crossed the river Don near Rostov. It split into two detachments. The 8th Rosiori Regiment advanced down the coastline and took Yeisk, an important objective for the control of the Azov Sea on 9 August and Primorsko-Ahtarskaya on 11 August. The 6th Rosiori Regiment moved to the interior and occupied Krasnoarmeiskaya (9 August) and Slavianskaya (11 August), thus opening the way to Temryuk and Anapa. The Division advanced about 500 km in 7 days. Between 12 and 24 August, it occupied defensive positions on the river Kuban, waiting for the 6th and 9th Cavalry Divisions.

On 16 August the Romanian cavalrymen started to cross the Kurka Channel and by 20 the operation was over. The attack on Temryuk began on 23 and was carried out by the 6th Cavalry Division. In the evening it had reached the outskirts of the city. The following day, at 0400 hours, after an artillery preparation the Romanian troops stormed the city and took it three hours later. Thus the 6th Division trapped two Soviet marine brigades in the Taman Peninsula.

In the meanwhile, the 5th and 9th Divisions started to cross the river Kuban on 23 and continued their advance, preceded by the Mechanized Detachment "Col. Radu Korne". The latter reached the Nasurovo Heights, near Anapa, on 31 August. There it captured two Soviet 152 mm batteries, with which it bombed the city and the harbour. Soon Anapa fell to Romanian troops. After that, the two cavalry divisions advanced towards Novorosiysk, to support the German 5th Corps, which had the mission to capture this port.

The 6th Cavalry Division launched and offensive in the Taman Peninsula, between 2 and 9 September, and annihilated the Soviet forces there, establishing a link with the Axis troops in Crimea. From Kerch came 4 German divisions and 3 Romanian ones (10th and 19th Infantry Divisions and 3rd Mountain Division).

The 5th Cavalry Division approached Novorosiysk on 6 September and participated with the German 5th Corps at its capture on 11 September.

The Soviet Navy had lost two important bases (Anapa and Novorosiysk) and was forced to operate from unsuited ports. This and the establishment of two Romanian airfields in Crimea (Feodosya and Kerch) increased the security of Axis convoys.

The 5th Cavalry Division was moved together with the headquarters of the 3rd Army to Stalingrad. The Cavalry Corps (6th and 9th Cavalry Division and 19th Infantry Division) and the 3rd Mountain Division and the 10th Infantry Division subordinated to the German 5th Corps commanded by gen. Karl Allmendinger. The Romanian divisions occupied a defensive position on the Krimskaya-Krasnodar railway and on the coast between Taman and Novorosiysk.

Between 22 October and 10 December 1942, the 6th and 9th Cavalry Divisions and the 19th Infantry Division managed, through repeated attacks, to reach the Azovskaya – south Holmskaya – Kushnariov – Hill Lambina alignment, securing the railway which was vital to Axis operations in the Caucasus. The conditions they had to fight under were very difficult and the troops were very tired. They also had to man front lines beyond their possibilities: 3rd Mountain Division - 15 km, 19th Infantry Division – 24 km, 6th Cavalry Division – 24 km and 9th Cavalry Division – 30 km. Thus casualties were high. Between 1 August and 24 December 1942, the Cavalry Corps suffered 7,131 casualties (301 officers,121 NCOs and 6,719 soldiers).

Another Romanian unit which operated in the Caucasus was the 2nd Mountain Division (15,475 men), commanded by maj. gen. Ion Dumitrache. It was subordinated to the German 3rd Panzer Corps, commanded by gen. von Mackensen.

It entered combat on 22 August on the river Baksan and managed to establish an important bridgehead over it near Kysburun and after three days of hard fighting, on 25, the Romanian mountain troops took Hill 910, which was overlooking the Baksan Valley. It held the position in face of fierce Soviet assaults until 1 September. During the night of 1/2, the 2nd Mountain Division was ordered to evacuate the bridgehead and pull back and it did so in an orderly fashion, without any incidents. This decision was taken by the German command, after their forces failed to eliminate a Soviet bridgehead in the Sayuko Heights, which threatened the rear of the troops on Hill 910.

The fighting continued on the river Baksan. The Romanian mountain troops replaced the German forces facing the Soviet bridgehead. From two prisoners captured in that area, the Romanian commanders found out that during the night of 17/18 October, the Soviets were going to replace the troops. An attack was thus planned for the first hours of 18. Once the surprised was achieved, the vanatori de munte managed to infiltrate behind Soviet fortified positions, which fell one after another. The Romanian detachment (3 rifle companies, one heavy weapons company and one mountain artillery battalion) lost 6 men and another30 were wounded. About 400 prisoners were taken and many more were killed. The Soviet bridgehead was eliminated, to the delight of marshal von Kleist.

By 19 October the 2nd Mountain Division had captured 1,858 prisoners. Its new mission was to take the city of Nalchik. The assault over the river Baksan began in the morning of 25 October, after a powerful 10-minute artillery preparation and aerial bombardment. The division had the 4th (8th and 15th Battalions) and 5th Mountain Groups (9th and 16th Battalions) in the first line. In reserve were the 7th and 10th Mountain Battalions. The villages Kysburun and Chengem were taken and fighting was still going on in Kishpek at nightfall. The following day, the reserves were also committed into battle. The Soviets were pushed back to their positions in Nalchik and the division started the assault on the city itself. By 28, after some very brutal street fighting, the mountain troops had occupied it. Casualties were about 820. The number of Soviet prisoners was 3,079. Maj. gen. Dumitrache received the Mihai Viteazul Order and the Ritterkreuz.

Between 1st July and 31 October 1942, the Romanian forces engaged in the offensive towards Stalingrad (see the article about the 6th Corps) and in the Caucasus suffered 39,089 casualties (9,252 dead, 28,249 wounded and 1,588 missing).

On 3 November, the offensive was resumed and the 2nd Mountain Division advanced towards Alagir, which it passed by on 5. To mark the October Revolution (7 November) the Soviet forces launched a counter-offensive and managed to intercept Axis communications on the Nalchik-Beslan-Ordyonikidze and Nalchik-Alagir-Ordyonikidze roads. Thus a part of the 3rd Panzer Corps fighting Ordyonikidze was encircled. The 2nd Mountain Division attacked the latter road near Mairamadag on 12 November re-establishing a link with the German armored forces, which retreated during the following night. The Romanian troops remained on defensive positions after that. Between 20-25 November, the Soviets tried to brake through the lines of the 2nd Mountain Division, but we repulsed time and time again.

Because of the general situation on the Eastern Front, on 4 December a general retreat started in the Caucasus.