Invasion of Poland
106 / 298 were used in the invasion, with 218 in the German forces, and 79 in Slovakian forces.
112 were assigned to the 1st Light Panzer Division for the invasion of Poland. They fought a battle to establish a bridgehead over the River Warta on September 3, 1939. The 37 mm guns provided much fire support from behind the infantry that were crossing the river. During its 8 day, 497 miles/800 km advance, the Panzer 35(t) was mechanically reliable, although it was found that it had heavy maintenance requirements. 12 were destroyed and 65 damaged.
In other actions the 37 mm gun was sufficient against the Polish TK and TKS tankettes.
Invasion of France
The 1st Light Division was upgraded to the 6th Panzer Division and 116 Panzer 35(t)s were used in France. The 6th, 7th, and 8th panzer divisions were outfitted with Czech tanks.
Invasion of Russia
189 were still available at the beginning of operation Barbarrosa. Most of these were with the 6th Panzer Division. It lost most of them in the early months, and especially in early December 1941 around Klin (close to Moscow).
During the 1st winter in Russia the pneumatic steering system froze easily.
Some PzKpfw 35(t)s were kept in reserve in Germany and were used in September 1941 to outfit the 22nd Panzer Division. This was sent to the Eastern Front in the Spring of 1942. It used them in it's drive to Stalingrad in the summer of 1942. These were destroyed with the 6th Army at Stalingrad.
By June 1, 1942, there were still 167 available. In the spring of 1942 the rest were withdrawn from frontline units.
Germany supplied Bulgaria 36 in 1940. They were also supplied to Romania and Slovakia in 1939.
The Slovak Fast Division still used many of the LT38 during its retreat from the Caucasus in the winter of 1942-1943.
During the Slovakian national uprising in August 1944, they were used against the German forces, but were quickly destroyed.
A regiment was used by the 1st Armored Division, but was destroyed with the encircled German 6th Army at Stalingrad.