BAGHDAD — Vice is making a comeback in this city once famous for 1,001 varieties of it.

Gone, for the most part, are nighttime curfews, religious extremists and prowling kidnappers. So, inevitably, some people are turning to illicit pleasures, or at least slightly dubious ones.

Nightclubs have reopened, and in many of them, prostitutes troll for clients. Liquor stores, once shut down by fundamentalist militiamen, have proliferated; on one block of busy Saddoun Street, there are more than 10 of them.

Abu Nawas Park, previously deserted for fear of suicide bombers seeking vulnerable crowds, has now become a place for assignations between young people so inclined. It is not that there are hiding places in the park, where trees are pretty sparse; the couples just pretend they cannot be seen, and passers-by go along with the pretense.

It is a long way from Sodom and Gomorrah, but perhaps part way back to the old Baghdad. The Baathists who ruled here from the 1960s until the American invasion in 2003 were secular, and more than a little sinful. Baghdad under Saddam Hussein was a pretty lively place, with street cafes open until 2 or 3 a.m., and prostitutes plying their trade even in the bowling alley of Al Rashid Hotel.

“Everything is going back to its natural way,” said Ahmed Assadee, a screenwriter who works on a soap opera.

Men gather in cafes to smoke a hookah and gamble on dice and domino games. On weekends, the Mustansiriya Coffee Shop’s back room is crammed with low bleachers set up around a clandestine cockfighting ring. On one recent day, the 100 or so spectators were raucous while watching the bloody spectacle, but they placed their bets discreetly.

Gambling, after all, is illegal.

Walid Brahim, 25, a bomb disposal expert with the Iraqi Army, and his brother Farat, 20, an electrician, recently sat side by side at a table in the Nights of Abu Musa bar, on an alley off Saddoun Street, working their way through a bucket of ice and a bottle of Mr. Chavez Whiskey, an Iraqi-made hooch.

“This is great,” Walid Brahim said. “We used to buy alcohol and just drink secretly in our house.”

The bar is men-only, as pretty much all respectable taverns are, but the brothers look forward to an even brighter future.

“If this security continues,” Farat Brahim said, “within a year all the waiters will be girls.”

The local police, weary of years of dodging assassins and cleaning up after car bombings, are blasé about a little vice.

“Today we are dealing with more normal things. All the world is facing such problems,” said Col. Abdel Jaber Qassim Sadir, assistant police chief in Karada, a central Baghdad neighborhood.

“Prostitution, this kind of behavior cannot be stopped,” Colonel Sadir said. “It’s very hard to find it in public; it goes on in secret, isolated places.”

Actually, not so secret. There are a half-dozen night spots in Karada now where the entry fee is $50. With $150 a week considered a good wage, customers would not pay that much merely for the privilege of drinking.

At the Ahalan Wasahalan Club on Al Nidhal Street one recent night, the owner, Tiba Jamal, was holding court, as she usually does, on the dais at the front of a room with a mostly empty dance floor and lots of tables.

Ms. Jamal calls herself the Sheikha, or a female sheik, an honorific title she has apparently adopted. She dresses in a head-to-toe, skin-tight black chador, and she is adorned with several pounds of solid gold bracelets, pendants, necklaces, earrings and rings, her response to the financial crisis.

The female workers in the nightclub wore rather less clothing, but nothing that would be considered risqué on a street in Europe — in August. At one point in the evening they outnumbered the men, as they sat in a big group until being summoned to one of the men’s tables.

“It’s nice to see people having fun again,” Ms. Jamal said.

One regular customer said, “You can have any of those girls to spend the night with you later, only $100.” First, though, patrons are expected to spend a few hours buying $20 beers or even more costly whiskey.

A young woman who said she was 28 but looked 18 sat smoking, and downing soft drinks while her “date” drank Scotch. A university student, she would give her name only as Baida, but she was frank about her nighttime profession. Had something happened to force her into this? “No,” she said. “I go out with men so I can get money.” To support her family? She seemed stunned by the question. “No, for myself.”

One police detective said he would not dream of enforcing the law against prostitutes. “They’re the best sources we have,” said the detective, whose name is being withheld for his safety. “They know everything about JAM and Al Qaeda members,” he said, using the acronym for Jaish al-Mahdi or Mahdi Army, a Shiite militia.

The detective added that the only problem his men had was that neighbors got the wrong idea when detectives visited the houses where prostitutes were known to live. They really do just want to talk, he said.

“If I had my way, I’d destroy all the mosques and spread the whores around a little more,” the detective said. “At least they’re not sectarian.”

Others are uncomfortable with the prostitutes’ presence.

“It is terrible to see prostitution increased like this,” said Hanaa Edwar, secretary general of the Iraqi human rights group Al-Amal. “These are women from displaced families, poor people, people who have to sell themselves to get money for their families and children.”

She was incensed after she raised the subject before the Iraqi Parliament. “They were shocked and didn’t agree to open discussion on this issue,” she said. The shock, she said, was that she dared to mention the problem.

Al Amal commissioned a report last year that surveyed prostitutes working on the streets in Baghdad. One was a 15-year-old girl who had been thrown out of school for dressing inappropriately, then took to prostitution, the report said. Another was an 18-year-old forced to become the second wife of an older man; she ran away and had no other way to support herself. One girl was 12.

Certainly, vice often has an ugly side. During a recent undercover operation in Karada aimed at a human trafficking ring, a pimp offered a plainclothes officer an opportunity to buy a young woman to take to Syria, according to a detective, who spoke on the condition of anonymity because he was not authorized to discuss the sting.

Drug abuse, at least, is one problem that has not shown up much, or has stayed well underground, the police say. “The only problems we see are some illegal pills occasionally,” Colonel Sadir said.

Not surprisingly, the Baghdadis’ drug of choice is Valium, the colonel said.

Most people have had enough excitement these past six years just staying home.

Riyadh Mohammed, Suadad al-Salhy and Muhammed al-Obaidi contributed reporting.