The diuscovery was made at a location known as Banada, Tourlestrane, Tubbercurry.
A nine year old boy was found in the house with stab wounds. He was removed from the scene by Air Ambulance and taken to Sligo Regional Hospital and was pronounced dead a short time later.
A 21 year old man was found deceased in an outside shed at the same location.
The state Pathologists office has been notified.
The scene is preserved pending a Garda technical examination.
Investigations are continuing.