A panel of three judges in the Tel Aviv District Court dismissed the assault conviction of former MK Mohammed Barakeh of the Hadash party on Sunday.
Barakeh is accused of attacking a right-wing activist during a demonstration.
Much of the dismissal is due to the age of the accusation, the justices said.
MK Barakeh was convicted in March 2014 of assaulting a right-wing activist demonstrating against extreme left activists during the Second Lebanon War in 2006.
After the incident, Barakeh was charged with insulting a public servant, attacking a public servant, and disturbing a policeman in the line of duty.
MK Barakeh, according to the indictment, approached one of citizens at the protest who was documenting what was happening, and began punching his elbows and ribs.