The legislative district of San Juan–Mandaluyong was the combined representation of the Metropolitan Manila municipalities (now highly urbanized cities) of Mandaluyong and San Juan in the Regular Batasang Pambansa (1984–1986) and the lower house of the Congress of the Philippines (1987–1995).
These two municipalities were separated from the province to form the Metropolitan Manila Area on 7 November 1975 by virtue of Presidential Decree No.
The combined representation of the two municipalities lasted until the abolition of the Regular Batasang Pambansa in the aftermath of the People Power Revolution in 1986.
7675 and its subsequent approval by plebiscite on 4 April 1994 converted Mandaluyong into a highly urbanized city.
[4] Per Section 49 of R.A. 7675 Mandaluyong was constituted into its own congressional district, which effectively created separate representation for San Juan as well.