A 75-year-old man has died in a house fire at Morphett Vale in Adelaide's south overnight.

The Metropolitan Fire Service said they were called to the Grazing Avenue home just after 3:00am.

The house was well alight when crews arrived.

It took them about 20 minutes to extinguish the blaze.

The MFS said another man managed to escape the building.

He suffered minor injuries and was taken to hospital for treatment.

The MFS said the cause of the fire was believed to be accidental and damage to the home was estimated at $200,000.

A report will be prepared for the coroner.