Bitossi cycled for three years as an amateur and became a professional in October 1961, after he had reached the required age of 21.

[1] As a professional cyclist, from 1961 until 1978, he won a total of 171 races.

In 1967 he won the Tirreno–Adriatico, Giro di Lombardia and Coppa Agostoni, while the following year he became the first Italian to win the points classification in the Tour de France.

[3] In 1972 he became famous for his near victory at the World Championship in Gap, France, where he was beaten by only a few meters by his teammate Marino Basso.

[3] Bitossi was nicknamed Cuore matto ("Crazy heart") due to a cardiac arrhythmia which often compelled him to stop midway in a stage.