The election to fill the state House seat vacated by Peter Koutoujian will be held May 10, and the primary will be held April 12, according to an announcement today from the secretary of state’s office.
Koutoujian, a Waltham Democrat, resigned last week to be sworn in as Middlesex County sheriff.
Four Democrats have expressed interest in replacing him: Newton Aldermen Allan Ciccone Jr. and Scott Lennon, who is president of the board, and Waltham City Councilors Gary Marchese and Robert G. Logan.
The 10th Middlesex District seat includes parts of Newton, Waltham, and Watertown.
The deadline for filing nomination papers, which require 150 certified signatures, with municipal registrars is February 28, and the papers must go to the secretary of state’s office by March 8.