Luisa Pimentel Ejército–Estrada[1] (Tagalog pronunciation: [pi.mɛnˈtɛl ʔɛˌhɛːɾ.sɪˈto]; born June 2, 1930), commonly known as Loi Ejército, is a Filipino politician and physician who last served as a Senator of the Philippines from 2001 to 2007.

[3] Due to Estrada's extramarital affair with Guia Gomez in the 1960s, Ejercito separated from her husband for 18 years and moved to the United States with their three children.

[3] After her husband was deposed in the Second EDSA Revolution in January 2001 and replaced by Vice President Gloria Macapagal Arroyo, she ran as a candidate of the Puwersa ng Masa opposition coalition for a seat in Senate.

[9] In January 2014, letters sent to the Department of Agriculture showed that Ejercito allocated her pork barrel to at least two non-governmental organizations linked to Janet Lim-Napoles during her Senate term.

[10] In June 2014, she was named as the personal physician of her son Jinggoy, who was one of the senators implicated and detained for their alleged involvement in the pork barrel scam.