The state Board of Health had considered the requirement after the June death of a three-year-old who was accidentally left in his grandfather's vehicle.
The Board of Health decided workers can voluntarily contact parents if a child is late or absent.
Gov. Haley Barbour signed into law this year a bill that "an agreement may be made'' by a day care to contact a parent or guardian "if the child does not arrive at the facility within a reasonable time.''
On June 9, police say Robert Dossett, 61, forgot to take his grandson, Andrew Dossett, to day care on his way to work. The child died of heat stroke in a vehicle.
Dossett initially was charged with manslaughter and culpable negligence, but he was not prosecuted.