The two did not get along for a long time; the traditionalist ways of the father clashed with the creativity of the son, so Maurizio in 1974 gave life to his own company which he called Castelli and choosing a scorpion as his emblem.

Champions such as Eddy Merckx, Bernard Hinault, Francesco Moser, Giuseppe Saronni, Ercole Baldini and Silvio Martinello chose Castelli clothing for their races.

In the following decade, riders such as Laurent Jalabert, Carlos Sastre and Andrea Peron wore Castelli, as well as many important teams such as Roslotto, Refin Ceramiche, Tenax, Tinkoff and Saunier Duval.

In 2003, Giordano Cremonese, president of Manifattura Valcismon, the parent company of the Sportful brand, decided to buy Castelli and transfer it from Rosate to Fonzaso.

In 2009, Castelli became part of the supplier brands of Cervélo TestTeam which included, among others, Carlos Sastre, Thor Hushovd and Heinrich Haussler.