The district was first formed ahead of the 1943 Philippine legislative election following the ratification of the Second Philippine Republic constitution which called for a unicameral legislature composed of delegates from all provinces and chartered cities in the country.[4] Iloilo, a chartered city since 1936, elected Fortunato R. Ybiernas to the National Assembly, who was joined by then-mayor Vicente R. Ybiernas as an appointed second delegate.[5] The district became inactive following the restoration of the House of Representatives in 1945 when the city reverted to its old provincial constituency of Iloilo's 2nd congressional district.[3] In the unicameral Batasang Pambansa that replaced the House, Iloilo City was not entitled to its own separate representation despite being a highly-urbanized city. Instead, it formed part of the multi-member Region VI's at-large district for the interim parliament from 1978 to 1984 and Iloilo's at-large district in the regular parliament from 1984 to 1986.[3] The city-wide electoral district was only restored in 1987 under a new constitution.[6]
