The 35-year-old Cipollini announced his retirement in a statement last week, citing his bitterness at not being invited to the Tour de France as one of the reasons. He held a news conference about the decision Monday, and sent a slightly mixed signal.
"This is what I want, to leave cycling,'' he said. "Second thoughts? I've never had many of them.''
But he also said that "within 15 days'' he could rethink his decision if he misses the sport.
Cipollini, nicknamed "SuperMario," had one of his best seasons this year, taking six stages of the Giro d'Italia and winning the Milan-San Remo classic and the Ghent-Wevelgem race.
In his statement last week, Cipollini cited "the bitterness of not being able to compete'' in the Tour de France and frustration with his team sponsors to explain "this drastic decision.''
As Italy's best sprinter, Cipollini had been expected to be the Italians' top man at the world championships in Portugal this autumn.
In 1999, he became the first rider since 1948 to capture three consecutive stages of the Tour de France. And in this year's Giro, he moved one short of the career record of 41 stage wins long held by Alfredo Binda.
Cipollini had been captain of the Acqua e Sapone team, which was not invited to the Tour de France because the Italian star "had indicated a preference for the Giro and the Tour of Spain,'' Tour Director Jean-Marie Leblanc has said.
Cipollini had also made a habit of pulling out of the Tour before its finish.