The march wound along the Neapolitan waterfront
Thousands of Italians have marched through Naples in one of the largest anti-mafia protests of recent years.
Police said 100,000 people gathered for the protest, held annually on the first day of spring.
Names of some of those killed by the mafia were read out over loudspeakers as people honoured friends and loved ones, carrying flowers along the route.
They called for more police action against mafia clans, who have killed more than 900 people in recent decades.
Speaking to the crowds Antonio Bassolino, president of the Campania region, declared the mafia "are not eternal".
Both the traditional Sicilian Mafia and the Camorra, the Naples-based organisation, "can be beaten", Mr Bassolino told the protesters.
He called for more resources for regional police forces left to battle organised crime, adding: "Our byword should be 'continuity,' because we must fight 365 days a year against the mafia."
But some victims of Mafia violence said they remained sceptical about prospects for the future.
"I am angry and less optimistic than 17 years ago, when my brother was slain," Rita Borsellino told the AFP news agency.
Her brother, a judge, was assassinated in the centre of the Sicilian capital, Palermo.
"The Mafia have changed, they have become more dangerous, better inserted into the web of power," she added.
Among those who joined the march was investigative journalist Roberto Saviano, the author of mafia expose Gomorrah - now an internationally-acclaimed film.
The 29-year-old has received death threats since publishing his book, which focuses on the Neapolitan Camorra, and now lives under police protection.
Nationwide interest in the mafia was rekindled with the release of the film, Gomorrah, which won multiple prizes at a number of film festivals.
It tells the tale of a ruthless, adaptable organisation, that is mostly a work of fiction but which closely mirrors Italy's reality.
Organised crime in Italy is dominated by four mafia clans: Sicily's Cosa Nostra; the Camorra around Naples; Calabria's 'Ndrangheta; and the Sacra Corona Unita, in Puglia.
The Italian authorities have hit the Cosa Nostra hard in recent years, says the BBC's Mark Duff in Milan, but other groups maintain their grip and have seen their influence spread.
The global economic downturn has also thrown up fresh money-making opportunities for the mafia - such as lending cash to credit-starved businessmen.