A mother wept in the dock as she admitted killing her three young disabled children.
Tania Clarence, 42, pleaded guilty to the manslaughter of Olivia, four, and three-year-old twins Ben and Max by diminished responsibility.
But Clarence, of New Malden, south London, denied murdering the three children between April 20 and 23 when she appeared at the Old Bailey.
Clarence was tearful as she entered her pleas in the dock as her husband Gary looked on nearby.
A date was set for a three to four-week trial to start on February 21 next year.
The defendant was remanded to a secure mental hospital.
Police were called to the family's five-bedroom home in Thetford Road in the wealthy south-west London suburb of New Malden at 9.30pm on April 22 where they discovered the children, who were pronounced dead at the scene.
All three of Clarence's young children suffered from type 2 spinal muscular atrophy. Also known as floppy baby syndrome, the genetic condition leaves children with little control of their movements and can drastically shorten life expectancy.
Clarence was treated for cuts at St George's Hospital in Tooting, south London, and charged on April 24.
A further pre-trial hearing will take place on October 3.