It happened on U.S. Highway15/501 at Wave Road.
The North Carolina Highway Patrol said a Pittsboro police officer found the cyclists in the middle of the highway about 11:30 p.m. Thursday.
Investigators said 41-year-old Ivin Levander Scurlock, of Carrboro, died at the scene. The second bicyclist, identified as 40-year-old Alexandria Nicole Simou, of Chapel Hill, was taken to UNC Hospital where she was last listed in critical condition.
Authorities said Scurlock was wearing a reflective vest at the time of the accident.
"She was a really nice person. She didn't deserve to be hurt like that," said a friend of the victims, Dirck Martin. "Ivan was nice guy. He didn't deserve to have his life taken away."
Authorities are currently looking for a vehicle with front-end and windshield damage, but they did not know the make and model. They also said speed appeared to be a factor given the point of impact and where both victims ended up.
Anyone with information is asked to call the Hillsborough Highway Patrol at (919) 732-2551 or the Raleigh Highway Patrol Communication Center at (919) 733-3861.