Six times, Huntsman softly replied, "Guilty."
She faces up to life in prison on each count when she is sentenced on April 20.
As part of a plea deal, prosecutors agreed to recommend that she serve her sentences concurrently to one another.
Utah County Attorney Jeff Buhman told the judge that prosecutors also will write a letter to the Utah Board of Pardons and Parole about Huntsman's cooperation in the investigation after the children's bodies were discovered in her garage 10 months ago.
"We'd be surprised if she ever gets out of prison," despite concessions on the part of the prosecution, Buhman said. "There are probably very few people at the Utah State Prison that are responsible for six murders."
The bizarre case has received both national and international media attention.
Huntsman is accused of killing the six infants shortly after birth during the period from Jan. 1, 1996, to Dec. 31, 2006.
"The defendant gave birth to six children," Buhman told the judge. "Those children were born alive. Immediately after each child's birth, she either choked or smothered the child to death."
Neither Huntsman's defense attorneys nor members of her family commented to the media after the hearing.
Buhman said prosecutors have kept in contact with a family spokesperson, and that her family supported Thursday's resolution.
Huntsman's long-kept secret began to unravel in early April, when her now-estranged husband, 41-year-old Darren West who had spent eight years in prison for drug crimes before being released into a Salt Lake City halfway house was retrieving some of his belongings at their Pleasant Grove home.
Inside the garage, West found the remains of a baby wrapped in plastic bags and a green towel and stuffed into a white box, sealed with electrical tape. Alerted to the grisly discovery, police later found six more infant corpses similarly stored inside other boxes.
Huntsman allegedly told investigators that she had killed six of the infants, while a seventh child was stillborn.
West and Huntsman have three living children together, all daughters, now ages 13 to 20.
Police have said that Huntsman used methamphetamine heavily and that her drug addiction was a motive for her crimes.
Pleasant Grove police Capt. Michael Roberts said in July that Huntsman told authorities she was using meth during the period when she allegedly smothered or strangled the infants and also was drinking during part of that time. The cost of feeding her addiction factored into the killings, Roberts said, adding that Huntsman alluded to a choice she was facing.
"She had to make a decision between the drugs and the babies," Roberts has said.
Why Huntsman decided to keep the corpses for so long is somewhat of a mystery. She did offer an explanation in her police interview, according to Buhman and Pleasant Grove Detective Dan Beckstrom, but Buhman said her reasons didn't make much sense.
"It truly is unexplainable," Beckstrom said, adding that he did not want to offer any more details about what she revealed to police.
Police have said that DNA testing on the seven dead babies confirmed that all of them five girls and two boys were fathered by her husband.
Huntsman has been held at the Utah County Jail in lieu of $6 million cash-only bail.