A 14-year-old girl presented with cataract as an initial sign of IDDM. Before the diagnosis of DM, she showed no acute symptoms, including ketoacidosis. Retrospectively, there had been faint signs of polyuria, polydipsia, and nycturia. Diabetic cataract is a rare complication in young diabetics and is usually associated with long-standing DM and poor metabolic control. Previous cases have a striking resemblance to our patient, thus suggesting that a small group of young diabetics have weak symptoms, but are nevertheless at great risk of developing diabetic complications.