Labor MP Tim Hammond has reigned so he can spend more time with his young family.
The MP was first elected in 2016 and says it has been an incredible privilege to sit on the benches in Canberra.
His resignation ahead of the next federal election will prompt a by-election in the West Australian seat of Perth.
Mr Hammond has a six-year-old daughter, a two-and-a-half-year-old daughter and a six-month old son.
"When I'm in my 70s I want to look back and think I was a good dad and was there for them," he told media.
The MP acknowledged his decision will be unexpected for some but said he and his wife had tried "everything under the sun" and he could not wait until the next election.