Two children were flown to Children's Healthcare of Atlanta at Egleston after an early Wednesday morning wreck on Mount Vernon and Jim Hood roads in North Hall.
They, along with two other children and an adult, had first been taken to Northeast Georgia Medical Center in Gainesville.
The Atlanta hospital did not release any information about the children's conditions.
The two other children and adult were in stable condition Wednesday night, according to a NGMC spokesman.
The wreck took place at 7:42 a.m., when a truck carrying the five people hit a tree, according to the Georgia State Patrol.
Other details weren't immediately available including the names of all involved. The four children are believed to be students of North Hall area schools.
This is the third wreck involving serious injuries in the last two days.
A wreck Tuesday morning on McEver Road at Gould Road killed Ehsanul Haque, 57, of Gainesville and seriously injured two others.
Haque was a passenger in the Nissan Maxima driven by Layla Pervin, 34, of Gainesville. The other passenger was Monia Samantha Hossain, 9, of Gainesville.
Pervin and Hossain were transported to Northeast Georgia Medical Center, but were in stable condition Tuesday.
Another wreck Tuesday morning at Friendship Road seriously injured three people, including two children.
A Toyota 4Runner carrying a father and his two children was traveling west on Ga. 347 when it struck a concrete mixer truck head-on.
"For unknown reasons, the Toyota 4Runner failed to maintain its lane and traveled into the eastbound lane," Georgia State Patrol trooper Daniel Joiner said. "That's where they struck head-on."
The father, Matthew Boozer, was flown to Atlanta Medical Center. Carter Boozer, 7, was taken to Children's Healthcare of Atlanta at Egleston and Katie Boozer, 9, was flown to Children's at Scottish Rite in Atlanta. The Atlanta hospitals would not release their conditions.