The two 22-year-olds posed in front of the sign - famous the world over for its inscription "Arbeit macht frei (Work makes you free)" - on Sunday, reported PAP.
They were both arrested and face charges of propagation of fascism.
The use of Nazi symbols is punishable under Polish law.
The two men study history in Hungary, according to the report.
Auschwitz-Birkenau was the largest Nazi concentration camp the Germans built in Poland during World War II.
The majority of the at least 1.3 million inmates murdered in Auschwitz were Jewish.