The controversial law, approved Wednesday despite being condemned as a "war on the poor," will make al fresco snoozing forbidden in most downtown areas, if beds are available in established shelters.
It will be a misdemeanor punishable by up to six months in jail and a $1,000 fine.
"It's criminalizing the homeless," the Rev. Leonard Jackson, director of the city's Faith Organizing Alliance, complained during a City Hall protest before the law was approved.
"This is the most disgusting and embarrassing policy I have ever seen," said Annette Magnus, the executive director for activist group Battle Born Progress, according to the Las Vegas Review-Journal.
The law was passed by a 5-2 vote late Wednesday following a daylong City Council meeting that saw several protesters getting booted.
"Housing not handcuffs! Hey hey, ho ho — the war on the poor has got to go!" protesters chanted, according to the Reno Gazette Journal.
Mayor Carolyn Goodman, who sponsored the measure, insisted it was necessary to crack-down on a clear homelessness crisis there.
"This is flawed but it is a start," the mayor said, according to the Gazette Journal. "We have been having these conversations for 20 years, and we must have results."
The law applies to the city's downtown urban core, not the tourist-heavy Las Vegas Strip, which is overseen by a different jurisdiction. It goes into effect on Sunday, although the legal punishments will not begin until the new year.
The 9th U.S. Circuit Court of Appeals struck down a similar law from Boise, Idaho, last year — calling it unconstitutional to prosecute people for sleeping in public places when there aren't enough shelter beds.
The Las Vegas law was crafted to withstand a similar legal challenge by stressing it only applied "if beds are available" in shelters, City Attorney Brad Jerbic said.
Comment: Critics are calling this a 'war on the poor', but allowing homeless people to sleep on the streets when there are actual beds available isn't helping them nor is it helping the local community. The streets of Los Angeles are a prime example of how liberal 'anything goes' policies are destroying the city: