No immediate cause of death for the 18-month-old girl has been determined but Sgt. Pierre Tremblay of the Richelieu-St-Laurent regional police says she may have been suffering from heart problems.
The child was found unconscious around noon and emergency services were called.
Police say daycare workers attempted to revive the child and emergency workers took over when they arrived.
However, the infant was declared dead at a nearby hospital about an hour later.
The daycare centre was closed for the remainder of the day.
Support services were put in place for children and staff who were at the daycare when the tragedy occurred.