The Blue Room got its name from the colour of the blue painting of the walls. Among the floral ornaments there are half-figures of historical figures, mostly rulers. Here we find King Louis I. the Great, who gave town privileges to Bojnice in 1366, and his daughter Queen Mary I., who in turn elevated the nearby Prievidza to a rank of a royal town in 1383. Other owners of Bojnice Castle include King Matthias I. Corvinus, his illegitimate son John Corvinus and the later King John Zapolya. In the coffered ceiling there are gilded stars and three coats of arms of the owners of the castle: the Pálffy family (with a stag and a half-wheel), the Corvinus family (with a raven and a crescent moon) and the Zapolya family (a coat of arms divided into four fields with unicorns and silverwolves).

The Pálffy coat of arms was based on the coat of arms of Nicholas Pálffy, the founder of the family’s fame. He is referred to by the letters in the corners of the coat of arms “L B N P”, which are abbreviations of the Latin "liber baro Nicolaus Palffy", that is, the free baron Nicholas Pálffy. It was this successful anti-Ottoman warrior and loyal adherent of the House of Habsburg who received the title of count for his family in 1599. In the hierarchy of aristocratic ranks, the noble title of count is higher than baron but lower than prince.