20 year old Keith Harrison plead guilty to Manslaughter in Broome County Court.
Harrison admitted he caused the death of his 4 week old son Dylan in December.
They were at an apartment here on Monroe Street in Endicott.
Harrison said the baby was crying.
He told the judge he put his hand over the Dylan's mouth, and striking the child's head on a headboard while moving the boy.
Harrison will be sentenced to 15 years in prison in September.