Gardaí and the Fire Services arrived at the scene after on the Slievebloom Park area of Drimnagh at around a quarter to two this afternoon.
The fire was brought under control and the bodies of two men, thought to be in their late 60s and early 70s, were discovered inside the house.
Results of a post mortem on the bodies, which are due to be carried out tomorrow, and a technical examination of the scene will determine the course of the investigation.
At this point, however foul play is not suspected.
Anyone with information is asked to contact Sundrive Road Station.