Louisa Givens, of Ronkonkoma, was arraigned Monday in Suffolk County Court. She was charged in the death of her son and also with endangering the welfare of her 2 ½-year-old daughter.
Givens called 911 last May and said she had found her son, Kayden Givens, unresponsive.
Prosecutors said the baby had been left unattended for at least 17 hours before Givens called for help.
The child was pronounced dead at a hospital. The medical examiner's office determined the boy died of malnutrition and dehydration.
The defendant's daughter, Ava Johnson, was treated for malnutrition and placed in foster care.
Givens pleaded not guilty. Bail was set at $250,000 cash or $500,000 bond.