The taxi driver is believed to have suffered a medical episode at the wheel before the crash on Aldridge Road, Great Barr at around 3.45am on Sunday.
The driver, aged 60, suffered a cardiac arrest on his way to hospital and could not be saved.
Two people in the other vehicle suffered head injuries but are not thought to have been seriously hurt.
The road was cordoned off by police near the Asda Queslett store for several hours after the collision.
A spokesman for West Midlands Police said: "A man sadly died following a collision in Aldridge Road, Great Barr in the early hours of this morning.
"It happened at around 3.45am.
"It's understood a taxi driver, aged 60, suffered a medical episode at the wheel before crashing into another car.
"He suffered a cardiac arrest on route to hospital and couldn't be revived.
"Two people travelling in the other vehicle suffered head injuries but weren't seriously hurt."