A former executive millionaire mother has been sentenced to 18 years in prison for killing her eight-year-old autistic son in a luxury hotel room in New York City.

A jury convicted Gigi Jordan, 54, of manslaughter in the first degree in the New York state supreme court for the death of her son Jude Mirra at the Peninsula Hotel, Tribune reported.

Jordan claimed in her testimony that she did what she did because her son had been sexually abused by Jude's father and by other men in her life. She justified her act as her way of keeping the boy safe from her husband, who was planning to kill her and take her money. If that had happened, Jude would be left alone and defenceless to more torture.

She also claims to have tried to kill her herself, The New York Times reported.

Manhattan state Supreme Court Judge Charles Solomon did not believe her claims, saying that there is no credible evidence to support her story.

"All of her money, all of her resources, she decided to kill him. There were so many things she could have done," Solomon said, Fox New reported.

"You'd think the defendant would say, 'What a terrible thing I did! How could I kill my own son? How could I do that to my own flesh and blood?' But she never said I'm sorry."