It happened last summer, on July 31st in Katonah.
40-year-old Lisa Turkki was babysitting her nieces ages 7 and 9, while her sister and brother-in-law attended an outdoor concert.
Later that evening, Turkki called 911 and told the operator that she had stabbed her nieces.
The girls were rushed to the hospital for treatment of their injuries and have since recovered.
Turkki pleaded guilty Monday to the entire six count indictment against her.
She pleaded guilty to two counts of 2nd Degree Attempted Murder, two counts of 1st Degree Assault, and two counts of 4th Degree Criminal Possession of a Weapon.
She will be now committed to a secure facility for an examination in the custody of the State Commissioner of Mental Health.