The Masnago Castle Museum houses an important collection created thanks to numerous bequests from illustrious citizens. Inside its rooms, the fifteenth-century pictorial cycles, commissioned by the previous owners and referable to the style of the International Gothic, interact with modern and contemporary works.

The representations and decorative elements of the frescoes characterize the main rooms of the Museum: " Sala degli Svaghi ", " Sala dei Vizi e delle Virtù " and " Sala della Musica ". In these are exhibited paintings from the seventeenth to the twentieth century by authors such as Morazzone, Ceranino, Hayez, Cremona, Ranzoni, Balla, Pellizza da Volpedo, Enrico Baj and other important modern Lombard painters.

On the other hand, the works of sculptors of the caliber of Tavernari and of the Varese artist and designer Marcello Morandini are of a more contemporary character. The external structure of the castle is a combination of architectural elements. The oldest is the tower, a typical component of medieval defensive structures, whose presence is accompanied and softened by the fifteenth-century building and the seventeenth-century wing.

Walking through the corridors of the Museum, the visitor can try to admire that balance between past and present, ancient and contemporary, religious art and abstraction, which connects the "container" and its "content". Everything is contextualized within the Mantegazza Park, a city park characterized by an extraordinary wealth of plant species, which make it similar to a small botanical garden.