Nakira Griner entered her plea during an arraignment hearing Monday. The 25-year-old Bridgeton woman is charged in the death of 23-month-old Daniel Griner Jr.
Cumberland County prosecutors have said Griner initially reported that her son had been abducted on Feb. 8 and an intensive search was launched by law enforcement. But the child's burnt remains were found the next day in the yard of Griner's home.
Griner's public defender says she previously sought help for mental health issues and that she was suffering from postpartum psychosis at the time of her son's death.
Besides murder, Griner is also charged with disturbing human remains, tampering with evidence, child endangerment and false public alarm.
--The Associated Press contributed to this report.