Ashley Warden in Piedmont, Oklahoma received the fine when her toddler Dillan was caught urinating in the yard by a passing police officer.
Dillan was being potty trained at the time and was not near a toilet.
Ashley told News 9: "Dillan pulled down his pants to pee outside.
"[Then] the cop pulled up and asked for my licence, and told me he was going to give me a ticket for public urination."
Dillan's grandmother Jennifer added: "I said, 'Really? He is 3 years old', and he said, 'It doesn't matter, it is public urination'. I said we are on our property and he said it's in public view."
Ashley stated that she would be fighting the fine, as Dillan didn't finish peeing because he was interrupted by the police officer.
> Woman charged for urinating on man, sofa
> 11-year-old urinates on £22,000 worth of Apple MacBooks