Three family members died at Area Two in Mathare North after their houses were razed down on Tuesday night.
The deceased are a 35-year-old mother of two children aged 12 and 3 years.
They are said to have suffocated during the incident as they tried to salvage some of their belongings.
Reports indicate that they got trapped in the fire that broke out at around 11pm.
Several other houses were burnt down with victims counting untold losses.
Nairobi County Police Commander Rashid Yakubu said investigations are underway to establish the cause of the inferno.