The government says a new law that comes into effect Aug. 8 is meant to reduce serious abdominal or spinal-cord injuries in an accident.
The law will require children to be at least four-foot-nine, weigh at least 80 pounds or be nine years of age before their parents can ditch the boosters.
Manitoba's Highway Traffic Act currently requires car seats to be used until a child reaches the age of five or weighs 50 pounds.
Research suggests smaller children who are restrained with seatbelts without booster seats are 3 1/2 times more likely to be injured in a car crash.
They are also just over four times more likely to suffer a head injury.