Phthisis of the eye is an uncommon presenting sign of retinoblastoma. The authors report a case of bilateral retinoblastoma in a 14-month-old girl who presented with phthisis of the left eye. Enucleation of the painful left eye was performed. Spontaneously regressed, mostly calcified retinoblastoma was diagnosed. The patient underwent chemoreduction. Plaque radiotherapy and transpupillary thermotherapy were applied on the right side. Subsequent ophthalmoscopic examination revealed lesions showing "cottage-cheese" regression. Retinoblastoma should be suspected in any child presenting with phthisis bulbi of unknown origin and a detailed examination of the other eye should be performed.