A father and his three grown-up sons died of suffocation in Quetta after they left a gas heater on overnight.
The city is in the grip of a cold snap with temperatures falling to -8 degrees Celsius at night.
Police officials said Amanaullh Jan, 50, and his sons Habibullah, 30, Hafizullah, 26, and Mujibullah, 22 died of suffocation.
They were Pakistani nationals of Uzbek ethnicity.
The family was living in a home on Jan Mohammad Road.
The bodies were moved to the state-run Civil Hospital.