"We the jury, after further deliberation, still cannot reach a unanimous verdict," said Judge Glenn D. Kelley today in court, reading the jury's statement.
"I must declare a mistrial," Kelley said.
Kelley then sent forms to jurors, asking how they would have voted, and later, shared them with the court.
"I'll just tell you, it was not a single holdout. ... By my count, there were three votes for guilty and three votes for not guilty. ... It was actually a 3-3 split," he said.
In a statement after the ruling, State Attorney Dave Aronberg said: "My office will retry this case at the earliest opportunity. Due to ethical rules, I cannot comment further because this is again a pending case."
On Tuesday, after beginning deliberations earlier in the day, the jury told the court that they could not agree on a verdict. The judge sent the jury home to rest.
During the trial, prosecutors said that Dippolito, 34, allegedly had hired an undercover officer posing as a hitman to kill her then-husband, Mike Dippolito, in 2009.
Jurors were shown a video of Dippolito in a car with the fake killer for hire.
"I'm going to tell you how I'm going to do it and what exactly is going to get done," the undercover officer is heard telling Dippolito in the 2009 video. He then goes on to say that he will break into their house and her husband "gets two in the head."
"Between now and when it's done, you know, you're not going to have an opportunity to change your mind," the undercover officer says.
"No, there's no, like, I'm determined already, I'm positive, like 5,000 percent sure," Dippolito tells him.
In an exclusive interview with ABC News in December 2015, Dippolito maintained her innocence.
Dippolito denied ever wanting Mike Dippolito killed and said she did not hire a hitman to carry out a murder plot, that it was all fake and that she was just acting.
"Did you want your husband dead?" "Good Morning America" co-anchor Amy Robach asked.
"No, absolutely not," Dippolito said.
Her lawyers also argued that the investigation was tainted by Boynton Beach police, who were eager to be part of a reality show called "Cops." The police department denies any wrongdoing and says it was only trying to gather evidence.
In her first trial in 2011, Dippolito was convicted of solicitation to commit first-degree murder and sentenced to 20 years in prison. That conviction was overturned on appeal.
Jurors declined today to comment as they left the courthouse. The judge set a status check for Jan. 6.