| Abolition of mixed-member proportional representation for 25% of the seats in the Chamber of Deputies | |
| Date: | 18 April 1999 |
| Flag Image: | Flag of Italy (1946–2003).svg |
| Yes: | 21,161,866 |
| No: | 1,960,022 |
| Invalid: | 1,325,633 |
| Electorate: | 49,309,060 |
| Outcome: | Proposal failed as voter turnout was below 50% |
An abrogative referendum on the electoral law was held in Italy on 18 April 1999.[1] Voters were asked whether they approved of replacing the mixed-member proportional representation electoral system (in which 75% of seats in Parliament were elected in single-member constituencies and 25% by compensatory proportional representation) with one based solely on single-member constituencies, with the 25% of seats instead allocated to the second-placed in the constituencies with the most votes.[2] The proposal was supported by larger parties, but opposed by smaller ones.[2] Although the proposal was approved by 92% of voters, turnout was only 49.58%, resulting in the referendum being invalidated as the threshold of 50% was not passed.[3]