Chilaw electoral district was an electoral district of Sri Lanka between August 1947 and February 1989. The district was named after the town of Chilaw in Puttalam District, North Western Province. The 1978 Constitution of Sri Lanka introduced the proportional representation electoral system for electing members of Parliament. The existing 160 mainly single-member electoral districts were replaced with 22 multi-member electoral districts. Chilaw electoral district was replaced by the Puttalam multi-member electoral district at the 1989 general elections, the first under the proportional representation system.