Police were called to a report of a missing two-year-old boy in the West Cotton Close area of Northampton just before 6pm on Saturday (July 28).
Officers, family and local residents searched the area but the boy was recovered from the water of the nearby canal area at about 6.30pm.
Police officers administered CPR at the scene before paramedics attended.
The child was taken to Northampton General Hospital and later transferred to Glenfield Hospital in Leicester.
Efforts to revive him continued into the early hours of Sunday, however the boy died at 3.25am.
Police are supporting the family and working with them to establish the circumstances leading up to the death.
Witnesses to this incident, or anyone with information about it, can call Northamptonshire Police on 101 or information can be given anonymously to Crimestoppers on 0800 555111.