Police and the fire service are probing the cause of the blaze which broke out at Cameron House Hotel on the banks of Loch Lomond yesterday morning.
One person was pronounced dead at the hotel, which is situated near Balloch, while another died after they were taken to hospital.
A couple and their young son were also taken to hospital but have been discharged.
Many of the 200 guests at the hotel were evacuated but have since returned home. Others have been transferred to nearby lodges, the BBC said.
At one point more than 70 firefighters were tackling the blaze, which started at around 6.40am on Monday.
Police have said the full circumstances of how the fire started had yet to be established.
Cameron House resort director Andy Roger offered his condolences to the families of those who died.
He said: "Tragically, the authorities have confirmed two fatalities from the fire. In addition, three individuals were transported to the local hospital, but have since been discharged.
"The safety and well-being of our guests, employees and neighbours is our first priority, and our deepest condolences are with the families of those affected."
