The advent of fascism pushes Costetti to join the Manifesto of anti-fascist intellectuals promoted by Benedetto Croce in 1925, then to move away from Italy for fifteen years, traveling between Paris, Oslo and Utrecht, while his vision of art tends to sublimate and becoming increasingly spiritualized, Costetti died in Settignano (Florence) in 1949, shortly after his return to Italy.
The artist's works are today mainly preserved in the Civic Museums of Reggio Emilia, the Gallery of Palazzo Pitti in Florence and numerous private collections.