The EagleMed chopper went down near the Northwest Expressway in Oklahoma City just before 6:00 a.m. Friday morning.
Reports are saying that all three aboard were employees; two died, a third was critically injured.
A person who had rushed to the scene to help was also hurt, but not seriously.
Witnesses say the pilot appeared to have fought to keep the aircraft from hitting the buildings.
It ended up crashing in the parking lot between the two buildings.
EagleMed flies out of the Integris Baptist Medical Center, and the chopper had reportedly lifted off there just before the crash.
EMSA has confirmed they have transported two people to the hospital from the scene.