A by-election was held on 13 April 2019 for the Negeri Sembilan State Legislative Assembly seat of Rantau. The seat became vacant after the uncontested election of incumbent Mohamad Hasan of the United Malays National Organisation (UMNO), a component of Barisan Nasional (BN) coalition was declared null and void. The nomination day was on 30 March, with a about 2-week campaigning period until election day. The constituency has 20,926 registered voters- 20,804 ordinary voters, 118 early voters and four absentee voters.