Arizona now has the toughest immigration laws in the country.
The state also has the most illegal border crossings in the US.
The new law requires local police to stop and demand proof of citizenship from anyone suspected of being an illegal immigrant.
"I see it like a malignant tumor. A tumor in the state of Arizona that if we allow it to grow and fester-will become a cancer in the entire country," Sharpton stated.
On Friday, Governor Jan Brewer signed the bill into law making failure to carry proof of citizenship or legal status a crime.
Any immigrant who can't produce the documentation can be arrested, fined $2,500 and jailed for up to six months.
"Decades of federal inaction and misguided policy have created a dangerous and unacceptable situation," said Governor Brewer.
The law also toughens restrictions on hiring illegal immigrants for day labor and knowingly transporting them.
Supporters dismiss concerns of racial profiling, saying the law prohibits the use of race and nationality as the sole basis for an immigration check.
Brewer has ordered a training course for officers.
But critics believe it opens the door to racial profiling.
"This law is anti-american, it's anti-latino, it's anti-immigrant, it is unconstitutional," Sharpton said.
It's an issue that's drawing raw emotions like at Saturday's rally in Queens.
"We can't even put into words the kind of insult that this legislation is for our communities," said Ana Maria Archila of Make the Road NY on Saturday. New Jersey Senator Robert Menendez expects the law to face court challenges.
"It is fundamentally wrong to be a second-class citizen just because you have a certain accent or you look a certain way, that's what Arizona is pursuing. That's why we need comprehensive reform, to secure our borders," stated Sen. Menendez.