A woman, having burn wounds, was found lying at Amherst Street area in the northern parts of the city, police said.
The unidentified woman was declared dead at the Medical College Hospital.
In the second incident, a middle-aged man was found lying at Shovabazar area in the morning hours, they said.
He was taken to hospital where he was declared dead.
The 55-year-old man, a resident of North 24 Parganas district, did not have any injury marks on his body.
"We have lodged separate cases and investigation was on to know the circumstances behind the deaths," they said.