State Sen. Jeff Mullins, a Republican representing a swath of southern West Virginia, says he's resigning because of business and family obligations.
Mullins, who has held the seat since 2015, chairs the Senate Banking and Insurance Committee.
The Senate district includes Raleigh, Wyoming and part of McDowell counties.
According to his biography, Mullins is a licensed insurance agent and chief executive of Employers' Innovative Network, which handles companies' payrolls, benefits, compliance and human resources issues.
In his resignation letter, effective Friday, he says it's "a pivotal time in my business as we grow throughout West Virginia and expand into other states."
Senate President Mitch Carmichael says Mullins brought a unique skill set to the Senate.