The latest explosion occurred at a public bathroom in a Rangoon railway station, witnesses said.
On Friday, a woman was killed by a blast in a railway station toilet in Nay Pyi Taw, the new capital.
And another man died, and four people were injured, when a bomb exploded in Pyu, north of Rangoon.
The government has blamed both incidents on the Karen National Union, a group fighting for greater autonomy for the ethnic Karen people.
The state-run newspaper, the New Light of Myanmar, said in both cases it was the bomber who was killed in the process of handling the bomb.