Kaushik Patel was spared a possible death sentence in exchange for the guilty plea. He will spend the remainder of his life in prison. State's Attorney Joseph Birkett agreed not to seek the death penalty during talks with defense attorneys.
Patel was seriously injured in the November 2007 fire, but has since recovered.
Patel admitted dousing 7-year-old Vishv Patel and 4-year-old Om Patel with gasoline in the shower of the family's home on Nov. 18, 2007 and setting them on fire. The boys suffered severe burns that led to their deaths months later.
He set his children on fire after becoming despondent over the state of his marriage.
The 35-year-old Kaushik Patel has recovered from burns suffered in the incident.
Members of Patel's family were in attendance when he entered his plea, but not his former wife, Nisha Patel.
(The Associated Press contributed to this report.)