However, Reyes was ordered disqualified by the First Division of the Commission on Elections (COMELEC) over her citizenship status. In its ruling, the COMELEC cited the Citizenship Retention and Re-acquisition Act of 2003, claiming that Reyes was still an American citizen and she had failed to renounce her citizenship. In addition, the ruling notes that Reyes did not submit sufficient evidence that she had been resident in Marinduque for at least one year, citing documents which point to her term as Provincial Administrator. The ruling was affirmed by the COMELEC en banc on May 14, 2013.
Despite this, Reyes continues to sit as representative of Marinduque, with the Reyes camp claiming that it is the House of Representatives Electoral Tribunal (HRET), and not the COMELEC or the Supreme Court, that should have jurisdiction over the case.
Incumbent governor Carmencita Reyes is running for a second term, having assumed the governorship after defeating then-incumbent Jose Antonio Carrion in the 2010 election, alongside her running mate, vice governor Antonio Uy, Jr. Although she was a guest candidate of the Liberal Party the previous election, having run as a member of the party-list group Bigkis Pinoy, for this election she is running as the Liberal Party candidate. Reyes' running mate is doctor Romulo Bacorro.
Uy has since left the Liberal Party and has decided to run for governor under the NUP, the party of Congressman Velasco. However, he does not have a running mate; instead, the NUP is endorsing Melecio Go of the Nacionalista Party for the position of vice governor. Go is currently a member of the Sangguniang Panlalawigan for the province's first district, and was elected in 2010 as an independent.
Carrion is seeking to retake his seat after losing the previous election to Reyes. Though he ran under the Lakas–CMD ticket in 2010, for this election he is running under the banner of the Nationalist People's Coalition. His running mate is Jose Alvarez, who previously sat as a member of the Sangguniang Panlalawigan for the province's first district.
Despite being disqualified by the COMELEC en banc, Regina Ongsiako Reyes was proclaimed anyway by the Provincial Board of Canvassers on May 15, 2013, although the camp of Lord Allan Jay Velasco attempted to stop the proclamation. Edwin Villa, the provincial election supervisor and head of Marinduque's Provincial Board of Canvassers, has since been replaced by Val Mendoza, the provincial election supervisor of Romblon, although it is unclear whether Mendoza assumed the position. Villa has since gone into hiding.