Rome on summer evenings is a festival of street fairs, music and outdoor films, and one of the most enchanting sites for the municipally organized events is the Isola Tiberina, a boat-shaped island in the middle of the Tiber River.

Kiosks on the island and the riverbank opposite sell sandwiches, clothes, soap and souvenirs while music blares from loudspeakers at outdoor pubs. Romans and tourists alike view movies under the stars. But the island is also home to the Fatebenefratelli Hospital, and patients there are having trouble getting to sleep.

They are not the only ones. From Alpine towns in the north to Sicily in the south, noise pollution has become a leading complaint in a country where having a carefree summer is a major preoccupation. Environmental teams measure decibel levels up and down Italy, ranking the clatter of silverware at outdoor cafes and the chatter of pub clientele as hazards of Italian urban life comparable to smog and uncollected trash.

In Turin, police have mounted Green Patrols to monitor excessive nightly noise downtown. Residents of the Quadrilatero Romano restaurant and bar district hung banners from their windows earlier this month pleading, "We want to sleep" and "Rest is golden."

In Milan, police patrols were extended to crack down on bars that stay open beyond 2 a.m. and to clear plazas of revelers, some of whom have been pelted by bags of water tossed from the apartments of irate local residents. In Naples, beach parties along the city's seafront have created late-night traffic jams featuring the roar of motorcycles.

In 1997, the central government ordered cities to zone commercial urban areas for maximum noise, with an upper limit of 70 decibels in industrial zones.

The effort was designed in part to shift discos and other thumping establishments to non-residential neighborhoods. However, only 12 percent of Italian towns bothered to set up the zones, according to Legambiente, a leading environmental group. As a result, bars and discos are scattered throughout Italian cities, and so are the pounding pop music, drunken talk and revved-up engines that go with them.

"Towns are just sitting on the issue," said Stefano Ciafano, a Legambiente activist. "We know they have more serious problems, but almost 10 years have passed. They should put in the rules."

Outdoor summer entertainment is one of Italy's most cherished traditions. For centuries, a stroll through the plaza was a key ritual for those interested in socializing and flirtation. Open-air movies, especially in villages without cinemas, became a favorite seasonal pastime, which persisted even after the advent of multiplex theaters and home video players.

Growing affluence, and the cars and motorcycles it made possible, enabled young people to escape the watchful eyes of their parents and travel around town in search of fun in plazas far from home.

One such romping place in Rome is Campo de' Fiori, an old, open-air market square that over the past few years has become ringed by bars catering to the young. The nightly cacophony of shouts, laughter and street music is reducing the value of apartments overlooking the square and other entertainment districts by as much as 40 percent, according to a study commissioned by Noise Mission, a group founded to advise residents on how to combat neighborhood noise.

The author of the study, Giorgio Campolongo, a Milanese professor of applied acoustics, said that real estate agents frequently give evening tours to prospective buyers of such property only on Mondays, when discos and pubs are usually closed. "The property market frequently puts a value on silence but tries not to reduce value due to noise, profiting from the lack of knowledge of the buyer," he said.

In Rome and other cities, sleepless neighborhood residents complain that young people are drinking more -- and socializing more loudly -- than they used to. They blame a growing taste for beer as well as the introduction of fruity, hard-liquor cocktails sold in bottles.

"Maybe I'm just getting old," said Maria Caputo, a housekeeper who has lived in the Campo de' Fiori neighborhood for 40 years. "But it seems to me that young people these days drink and drink and spread all over the street. We were happy with a little glass of wine at the bar, if we could afford it."

Tour operators have lured foreign travelers, who add to the inebriated din. For only about $17, tourists can sign up for a pub crawl that begins near the Colosseum with an all-you-can-drink binge and continues on to four dance halls where the first shot is included in the tour price. ("Go Free on Your Birthday," one advertisement flier urges.)

Disturbances in Camp de' Fiori have broken out frequently this summer, police say. Last month, youths threw tables at police who were trying to break up an impromptu midnight soccer game in the square.

This month, Rome banned drinking from bottles on city streets -- except for milk. "Our interest was only to reconcile the interests of residents with the thousands of people who frequent this plaza," said the city's commerce adviser, Daniela Valentini. But bottling company lobbyists complained that the ban was discriminatory and said that if the city wanted to improve public order in the plaza, it should provide more police.

The entertainment on Isola Tiberina is part of the city's "Roman Summer" program of outdoor concerts, exhibits and movies. Some of the events are sedate. Concerts at Teatro Marcello, an ancient Roman amphitheater, feature chamber and classical piano music. Local residents sometimes sit on their rooftop terraces to listen, and the music ends well before midnight.

But on the island, the rhythms of pop music sometimes persist until as late as 3 a.m.

"I came here because I suffered from the heat and fainted," said Valentina Visconti, an elderly patient at the hospital who was checking out after a restless night. "I couldn't sleep, so now I'm going home."

"The noise gets in even if the windows are closed. For a while, it cheers patients up, but then it becomes intolerable," said Silvia di Giuseppe, another patient.

Even the pope seems to have had it with Roman noise. Speaking at his Alpine summer retreat recently, John Paul II invited everyone to rediscover silence, "a blessing ever more rare in modern society."

Every night of the week, large groups assemble at the Colosseum to join a $17 pub crawl that ends in Rome's rowdy Campo de' Fiori. Excessive noise is blamed for lowering property values in some areas.