A number of 12 retinoblastoma cases were studied. We had in view a number of histopathological aspects (tumor type, neighbouring structures invasion) which are considered to be decisive in appreciating the vital prognosis. We mention that undifferential retinoblastoma of histopathological type was met in 8 cases and the neighbouring structures invasion was present in 7 of them. We also studied the ultrastructura of the tumor cells belonging to the malignant tumor.