The Pima County Sheriff's Department says deputies responding around 12:05 a.m. Saturday found 39-year-old Andrew Gaines dead at the scene and a 61-year-old man with severe injuries.
Deputies say Gaines was traveling westbound on Valencia Road and the 61-year-old was driving eastbound.
Authorities say a third vehicle rear-ended one of the cars after the initial collision. But the driver of that car was not hurt.
Investigators say speed may have been a factor and it's unknown if alcohol was involved.