National Court Judge Eloy Velasco is charging six of the seven with belonging to a terrorist group, while one is accused of collaboration.
Velasco says the seven provided money, cover and information to help six men who are suspected of having participated in the March 11, 2004, bombings to evade justice.
The morning rush hour attacks on commuter trains headed for the capital's main southern station killed 191 people and wounded about 1,800.
Four of the seven indicted are free, one is in custody and the whereabouts of two others are unknown.
Source: FoxNews