The Buchanan County prosecutor's office charged Shawn D. Winkfield-Maynard, 24, with involuntary manslaughter in the death of Kion Winkfield-Maynard.
According to authorities, the baby drowned at a home in the 800 block of North 5th Street on August 2.
A probable cause statement alleges Mr. Winkfield-Maynard left his son unattended in a bath tub with water for an extended period of time.
Police said two adults - the baby's father and an uncle - were home at the time. They told police the boy accidentally drowned in the bathtub.
Capt. Janice Rothganger said an officer assisted EMS with CPR, but the effort was unsuccessful. The baby was pronounced dead at the hospital.
Police say a warrant has been issued for Mr. Winkfield-Maynard's arrest. Anyone with information about his whereabouts can contact police at 816-271-4777 or the Crime Stoppers hotline at 816-238-TIPS.