Her office did not offer specific details about the threats, but it said they included "racially charged language," according to a statement Monday.
"We can confirm that the State's Attorney has received threats to her personal safety and security, a number of which have contained racially charged language," the office told ABC Chicago station WLS on Monday.
The announcement comes less than a week after the office released more than 3,800 pages worth of emails and text messages, including some where Foxx referred to the 36-year-old Smollett as a "washed up celeb who lied to cops."
Foxx made the comment to her top deputy, Joseph Magats, after she recused herself from the case.
Smollett was indicted on 16 counts after allegedly lying to Chicago police about being attacked in a hate crime.
“Sooo…...I'm recused, but when people accuse us of overcharging cases...16 counts on a class 4 (felony) becomes exhibit A,” Foxx texted Magats, according to documents released last week.
She also compared the case against Smollett to her office's sexual abuse case against embattled R&B singer R. Kelly, to whom she referred as a "pedophile."
"Pedophile with 4 victims 10 counts. Washed up celeb who lied to cops, 16. On a case eligible for deferred prosecution I think it's indicative of something we should be looking at generally," Foxx wrote. "Just because we can charge something doesn't mean we should. … it's not who we want to be."
The office eventually dropped the case against Smollett, saying it instead would focus resources on violent crimes. The move sparked backlash from the Chicago Police Department and Mayor Rahm Emanuel, who called the decision "a whitewash of justice."
City officials sued the actor for $130,000 in the wake of the dropped charges, seeking reimbursement for funds spent investigating what they called bogus hate crime allegations.
The lawsuit laid out a detailed account of the allegations against Smollett, who told police he was attacked Jan. 29 by two men who shouted homophobic slurs at him, wrapped a noose around his neck and poured an unknown liquid on him. The timeline includes a 41-point, blow-by-blow description, from when Smollett first met the Ola and Abel Osundario -- the brothers who say Smollett paid them to help stage the attack -- in the fall of 2017 until the final allegation that Smollett continued to be in contact with the brothers days after the purported attack.
A lawyer for Smollett, who portrays a gay musician on Fox's "Empire," said the actor "vehemently denies" accusations of making false statements to police and "will not be intimidated into paying the demanded sum."