Mindoro initially comprised a lone district for the purposes of electing representatives to the First Philippine Assembly in 1907.
When seats for the upper house of the Philippine Legislature were elected from territory-based districts between 1916 and 1935, the province formed part of the fifthsenatorial district which elected two out of the 24-member Senate.
During the Second World War, two delegates represented Surigao in the National Assembly of the Japanese-sponsored Second Philippine Republic: one was the provincial governor (an ex officio member), while the other was elected through a provincial assembly of KALIBAPI members during the Japanese occupation of the Philippines.
Upon the restoration of the Philippine Commonwealth in 1945, the province continued to constitute a single representative district.
[1] Pursuant to Section 6 of R.A. 505, the incumbent representative of Mindoro began to represent only Oriental Mindoro in the second half of the 2nd Congress, following the election of Occidental Mindoro's separate representative in a special election held on the same day as the 1951 senatorial elections.