Juvenile xanthogranuloma (JXG) of the iris is extremely rare in adults. A case of presumed JXG occurred in a 26-year-old woman who was seen initially with bilateral iris lesions and spontaneous hyphema in one eye. Diagnosis was based on the clinical picture and the finding of typical histiocytes obtained by paracentesis and examined by a polymer filtration (Millipore) cytopathologic techniques. Treatment with steroids (given orally and topically to the eye) resulted in a substantial decrease in the size of the iris lesion of the left eye. She has received no medications for 18 months and has shown no signs of progression or other complications 24 months after the initial diagnosis.