Police said Megan Huntsman, 39, gave birth to at least seven babies between 1996 and 2006 at her former residence in Pleasant Grove, a town about 35 miles south of Salt Lake City. One baby is believed to have been stillborn.
Huntsman was held on $6 million bail.
Darren West, Huntsman's estranged husband, was cleaning out the garage of the home, which is owned by his parents, and found one of the babies on Saturday. West then called Huntsman, who admitted her crime, according to police. Police were called, and six more deceased babies were found in the garage.
Huntsman is believed to be the mother of all seven, but DNA tests were ordered to confirm.
Huntsman and West have three daughters together: one is a teen, the others are adults. They live in the same house. The youngest daughter was born during the decade in which the other babies were killed, prompting investigators to ask why she was spared.
Police do not believe West knew about the pregnancies or the killings. Huntsman is the principle suspect in the babies' deaths.
West pleaded guilty in federal court in 2005 to two counts of possessing chemicals intended to be used in manufacturing methamphetamine, according to court records. In August 2006, he was sentenced to nine years in prison, but appealed three times.
The three daughters who were living in the house were good young women who have turned out remarkably well considering their father has been in prison, neighbors said.
The Associated Press contributed to this report.