Staghorn calculi (struvite stones) are a type of kidney stone that may occur with frequent kidney infections. They can be more serious than other types of kidney stones, because they are large stones and often occur with an infection.

They are called "staghorn" because on X-rays they look like deer (stag) horns.

Medical treatment, including antibiotics and surgical removal of the stone, is usually needed. Women are affected more than men because of their higher risk for urinary tract infections.