Intraocular foreign bodies are a potential factor threatening with loss of vision. The development of cataract and symptoms of ocular siderosis are the most common signs of ferrous metal entering the eye. We present a case of a 45-year-old man who reported to the hospital for planned cataract surgery. He denied the possibility of any past eye injury. Despite this, apart from the cataract, X-ray and CT scans confirmed the presence of an intralenticular foreign body and symptoms of ocular siderosis. Cataract surgery was successfully performed using phacoemulsification, and the metallic foreign body was removed. Intraocular foreign body symptoms may be overlooked by patients and even physicians and may occur with considerable delay. Hence, in patients with indirect symptoms of penetrating eye injury, the presence of an intraocular foreign body should not be ruled out, even if the patient denies this possibility.