The accident happened at about 4pm on FM 529 near Eldridge. Deputies say the UPS truck was pulling out of a driveway on the south side of 529, then made a left to go westbound when the truck clipped a Nissan Murano headed west in the outside lane.
The Nissan rolled over. The 80-year-old victim was pronounced dead at the hospital.
The delivery truck suffered front end damage. The UPS driver was on the scene and appeared to be unhurt.
Deputies say so far no citation has been issued, but the UPS driver could be cited for making an unsafe lane change.
The scene has been cleared after the earlier closure of westbound lanes of FM 529 during the investigation.