The bodies of the married couple - Kirils Nemcevs (32) and Lana Nemceva (23) - were found by police at a house in the town of Burton.
The toddler was saved by police who raced to the semi-detached home in a quiet street on Wednesday night.
A friend discovered the little boy asleep and the couple dead.
The child is now understood to be being cared for by relatives, according to British media.
Staffordshire Police were called to reports two people had been found "unresponsive" inside a home.
A force spokesman said: "The bodies of a 32-year-old man and a 23-year-old woman were discovered at the address. A two-year-old child was found unharmed at the property.
"The deaths are being treated as unexplained at this time and post mortems will take place in due course."
It is understood police are investigating whether the incident was a murder suicide.