Daniel Obajtek and Patryk Jaki, both of the right-wing Law and Justice (PiS) party, along with far-right lawmakers Grzegorz Braun and Tomasz Buczek lost their protections following a vote in Strasbourg on Tuesday.
The parliament's legal affairs committee had approved the move the previous week.
Obajtek, the former CEO of Poland's state oil company Orlen, faces two separate cases.
In one, he is accused of ordering Orlen petrol stations to pull copies of the weekly magazine Nie, which ran a cover featuring Pope John Paul II alongside a story about clerical paedophilia.
In the other, he is accused of giving false testimony, denying he knew a right-wing journalist, despite reports that the man had visited Orlen's headquarters and sought employment for his wife.
It is the second time Obajtek has had his immunity lifted.
Jaki faces a private lawsuit brought by Judge Igor Tuleya, who accuses the MEP of falsely claiming that he had knowingly authorised surveillance using the Pegasus spyware.
Buczek is accused of assaulting a woman during an election-night event, allegedly snatching a megaphone from her by force.
The case was brought through a private prosecution.
Braun has had his immunity lifted for the fifth time.
His latest case involves blocking access roads in Jedwabne, northeastern Poland, in July 2025, during ceremonies marking the 84th anniversary of the wartime massacre of the town's Jewish population.
A separate request from prosecutors, seeking his detention over an alleged attack on a gynaecologist in the southwestern Polish town of Oleśnica and obstruction of that investigation, was referred back to the regional capital Wrocław for supplementary information.
Polish MEPs are the most frequent subjects of immunity proceedings in the current parliamentary term.
Four other PiS members – Adam Bielan, Maciej Wąsik, Mariusz Kamiński and Michał Dworczyk – have also had their immunities lifted.
(ał)
Source: PAP, IAR