Vasyl Mosyakin, a candidate for MP from the Opposition Bloc in single-seat constituency No 132, has been found in Pervomaysk, Mykolayiv Region.
The press service of the regional police said that security guards at his Flora company found his body with a gun wound on the premises.
"The main scenario is a suicide. A hunting rifle was near the killed man's body. According to preliminary reports, the candidate for MP shot himself in the chest," it said.
A criminal case was opened over premeditated murder.
Mosyakin was also a city councilor in Pervomaysk and an ex-member of Viktor Yanukovych's Party of Regions.