State District Judge Belinda Hill accepted the plea and set a March 20 trial date.
Yates, who wore an oversized orange jail jumpsuit, appeared to have gained weight since her last appearance before Hill when the judge sentenced Yates to life in prison.
Prosecutors and Yates' attorney, George Parnham, said they are still negotiating a plea deal, but both sides said they've agreed not to discuss them publicly and are preparing for a retrial.
"We don't have an agreement and until there is some agreement, there is no agreement," Prosecutor Joe Owmby said Monday outside the Harris County courthouse.
Owmby noted last week that Yates would have to plead guilty to prompt discussions of how long or where should we be confined. Parnham wants Yates to be housed in a mental hospital instead of prison.
Parnham said, however, that he won't consider any scenario under which Yates must plead guilty in order to get the mental health care she desires.
"There will be no guilty plea," he said. "There are other avenues that can be explored, but that goes into the type of negotiations ... I don't want to break my bond with prosecutors about talking about plea discussions."
Parnham says Yates' mental health care is nonnegotiable.
"We are never shutting the door on trying to get this resolved so that none of us have to go through the ordeal of another trial," Parnham said. "That is something that no one relishes. ... Whether we can achieve that or not is mere conjecture."
Yates, 41, may remain in the custody of the Harris County Sheriff's Department until she is retried. She is currently in the Harris County Jail, where mental health experts keep a close watch over her, Parnham said.
Parnham, however, said he would try this week to get a bond set for Yates that would allow her to be housed at the Rusk State Hospital until her trial. Until last week, Yates had been imprisoned at East Texas' Skyview Prison Unit, a psychiatric prison.
An earlier attempt to get Yates transferred to the state hospital failed.
"That is a secure mental health facility," Parnham said. "She already has a doctor assigned to her at Rusk. The administrator has already approved Andrea's acceptance into that mental health facility. Everyone acknowledges that that is where Andrea can receive the best mental health care this state can offer."
Jurors rejected Yates' insanity defense during her original trial, finding her guilty of two capital murder charges for the 2001 deaths of three of the children drowned in the family bathtub: 7-year-old Noah, 5-year-old John and the youngest, 6-month-old Mary. Evidence was presented about the drowning of the other two children, Paul, 3, and Luke, 2, but Yates was not charged in their deaths.
The First Court of Appeals in Houston overturned Yates' convictions last January because the state's expert witness, forensic psychiatrist Park Dietz, testified about a nonexistent episode on television's "Law & Order" series. Dietz said a show about a woman with postpartum depression who drowned her children aired shortly before Yates killed her five children.
Prosecutor Kaylynn Williford would not say whether prosecutors will have another mental health expert evaluate Yates and review her medical records leading up to the new trial.
"We're not going to comment on trial strategy," she said.
To prove insanity in Texas, a defendant must prove she suffered from a severe mental disease or defect and did not know her actions were wrong.
, psychiatrists testified she suffered from schizophrenia and postpartum depression, but defense and prosecution expert witnesses disagreed over the severity of Yates' illness and whether it prevented her from knowing that drowning the children was wrong.