Article 36 of the Rome Statute of the International Criminal Court outlines qualifications and procedures for the election of judges.

http://www.un.org/law/icc/statute/romefra.htm

Qualifications: Judges must be persons of high moral character, impartiality, and integrity. Candidates must have established competence in criminal law/procedure or in relevant areas of international law such as international humanitarian law/human rights with extensive experience in a professional legal capacity relevant to the judicial work of the Court. All candidates must have excellent knowledge and fluency in at least one of the working languages of the Court.

Procedures: Nominations must be accompanied by a statement specifying how the candidate fulfills the necessary requirements. In the selection of candidates States Parties shall take into account representation of the principal legal systems of the world; equitable geographic representation; a fair representation of female and male judges; and legal expertise on specific issues such as violence against women or children. Each State Party must put forward one candidate that must be the national of a State Party. The Assembly of States Parties has the ability to establish an Advisory Committee on nominations. Judges are elected by secret ballot and those elected shall be the 18 candidates who obtain the highest number of votes and a two-thirds majority of States Parties present and voting.