The mother of a young man made the horrific discovery of his body and the body of his friend, both with substantial injuries, at a home the three shared in Geelong.

The two men, aged 23 and 30, were found dead in a bedroom at the rear of a home in Thatcher Court, Whittington, by the mother of the older of two, at about 10.20am on Wednesday morning.

Local detectives said the housemates had suffered what appeared to be stab wounds to their hands, arms and upper bodies.

Homicide detectives have not yet ruled out a murder-suicide and are treating both deaths as potential homicides while they await the results of forensic testing.