He is most famous for his character Valentina, created in 1965 and very representative of the spirit of the 1960s.

The Valentina series of books and strips became noted for Crepax's sophisticated drawing, and for the psychedelic, dreamlike storylines, generally involving a strong dose of eroticism.

His work was often politically motivated too, inspired by his Communist convictions.

[5] A film based on his work called Baba Yaga, featuring the character Valentina, was made in 1973.

[8] He was the author of some of the first wargames published in Italy to be widely circulated: He was also active as an animator and as an album cover designer.