The 2016 presidential campaign of Miriam Defensor Santiago, a then-incumbent Senator of the Philippines, was announced on October 13, 2015, at a book signing event.

[4] In August 2014, Santiago declared that she was open to run as president, saying that she was recovering and considering two other career options: entering the International Development Law Organization based in Rome, or authoring books about foreign policy at the Wilson Center in Washington, D.C.[5] In November 2014, Santiago announced that she will run for president if she is completely healed of cancer, saying that, at that time, 90 percent of her cancer cells had regressed.

[6] On October 26, 2015, a meet-and-greet event in front of UP students was held in UP Bahay ng Alumni (the same place where her co-presidential candidate Grace Poe announced her intention to run for president).

Santiago reiterated that she would run for the highest political position in the Philippines for the third time to stop the corruption in the government despite having stage 4 lung cancer:[7] I have passed through the hardest of physical trepidations and hardships known to man.

[8] It was reported in September 2014, that Santiago considered Rodrigo Duterte, Grace Poe and Gilberto Teodoro as her running mates.

[19] An advocate of the Reproductive Health Law (RHL), Defensor Santiago was not pleased by the 1 billion peso budget allocation cuts for contraceptives.

[45] Following a Catholic funeral Mass, she was interred at the Loyola Memorial Park in Marikina on 2 October, beside the tomb of her son Alexander, who died in 2003.