A 51-year-old grandmother from Pueblo and her grandson died in a one-vehicle accident.
Pueblo County Coroner James Kramer identified the victims as Mary Clementi and her six-year-old grandson, Devon Guerra.
They were killed when a car driven by Clementi veered off the road.
Three other children in the car were injured.
Pueblo Sheriff's Deputy A.J. Colletti said he believes Clementi and her grandson would have survived the crash if they had been wearing seat belts.