Section 118Omnibus Election Code of the Philippines (Batas Pambansa Blg. 881), Sec. 118

Disqualifications. - The following shall be disqualified from voting:

(a) Any person who has been sentenced by final judgment to suffer imprisonment for not less than one year, such disability not having been removed by plenary pardon or granted amnesty: Provided, however, That any person disqualified to vote under this paragraph shall automatically reacquire the right to vote upon expiration of five years after service of sentence.

(b) Any person who has been adjudged by final judgment by competent court or tribunal of having committed any crime involving disloyalty to the duly constituted government such as rebellion, sedition, violation of the anti-subversion and firearms laws, or any crime against national security, unless restored to his full civil and political rights in accordance with law: Provided, That he shall regain his right to vote automatically upon expiration of five years after service of sentence.

(c) Insane or incompetent persons as declared by competent authority.