The 10-storey Dubrovnik hotel, in the coastal city of Villa Gesell, collapsed early on Tuesday, with a local describing the scene as resembling a "horror movie".
Up to 15 people are believed to have been inside the hotel, which had recently been undergoing renovation.
Rescue teams were working at the scene attempting to free those thought to be trapped. The body of a man in his 80s was found in the debris, while one woman has so far been rescued.