A group of animal rights campaigners from the organisation Direct Action Everywhere (DxE), arrived at the fast food restaurant in London Road.
Activists sprayed blood on the floor while and held up posters.
"It violence, it's not food!" the activists chanted.
A group of animal rights activists from Direct Action Everywhere (DxE) wearing pig masks have been protesting at a McDonald's in Brighton — they chanted and covered the floor in fake blood to make their point #CapitalReports pic.twitter.com/Ap0rCUjaGh— Capital Brighton News (@CapBrightonNews) May 18, 2019
"Fake blood I spilt is nothing compared to the real blood McDonald's has spilled," said one of the campaigners.
Sussex Police officers arrived at the scene and urged the activists to leave, making one arrest, according to the group's Facebook page.