The daycare called police to report a worker found a small bag of marijuana in the infant's diaper.
It happened at the Waco Child Development Infant Center in Waco, Texas, reports CBS News Affiliate KWTX.
Police say the father apparently hid the "small baggy" of marijuana and then forgot about it.
When a worker went to change the girl, the drugs were found.
On Saturday, police arrested 23-year-old David Shepherd.
According to police records he was charged with abandoning or endangering a child. He was released from the McLennan County Jail on Sunday afternoon after posting bond.