Details of the circumstances were not immediately available.
The two Arlington incidents involved victims who were older than 65.
In the later of the two, Robert Bramwell of the District was killed late Friday night, in the 1700 block of N. George Mason Drive, Arlington police said.
They said Bramwell, 66, was hit after entering the roadway about 10:50 p.m.
By grim coincidence, the 1700 block of George Mason is within a block or so of the Virginia Hospital Center.
In the first of the Arlington incidents, a 77-year-old woman died Thursday after being struck the day before, police said.
Police said Martha Saltos, 77, of Arlington was struck and critically injured about 9:30 a.m. at Columbia Pike and South Four Mile Run Drive.
A preliminary investigation indicated that she was crossing the westbound lanes of Columbia Pike against the walk signal, police said.