The 54-year-old singer has received a warning from the company to adhere to its community guidelines, which ban photos that show "nudity" or "mature content".
Ironically, Madonna posted the photo sharing site's message on Instagram.
In the letter, the site owned by Facebook lets Madonna know that she shouldn't share photos that are not hers or pictures of illegal content.
"We value these guidelines, and believe that they will help keep Instagram a safe & fun place for everyone," the note reads. "It is important to note that continuing to violate them may result in a disabled account, or discontinued access to Instagram, without warning."
Madonna, who joined Instagram earlier this month, has posted snaps of her cleavage and behind, as well as pictures of Mexican artist Frida Kahlo, which could all be considered illegal or "mature."