Yassine Atar, 30, was formally charged "on account of terrorist assassinations and of participation as a leader in the activities of a terrorist group," a statement from the Belgian prosecutor's office said.
Yassine is the brother of Oussama Atar, 32, who remains at large and is believed to be one of the commanders of the attacks both in Brussels and in Paris, that were claimed by Islamic State.
Belgium has been on high alert since March 22 last year when suicide bombers attacked Zaventem airport and the Maalbeek metro station, killing 32 people and leaving more than 320 wounded.
Yassine was arrested just days after the 2016 Brussels attacks, found in possession of key to a hideout used by the jihadists that carried out the attacks in both European cities, Belgian broadcaster RTL has reported.
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After being arrested in Iraq in 2004 following the US-led invasion of the country, Oussama Atar spent time in various jails including the notorious Abu Ghraib prison used by American forces.
Released in 2012, he returned to Belgium where intelligence and police forces have faced fierce criticism about the development of jihadist networks in Brussels.
The Atars are cousin of the El Bakraoui brothers who blew themselves up in the Brussels airport and metro attacks.