Eighty-five cases of retinoblastoma seen at the Instituto Nacional de Enfermedades Neoplásicas of Lima, Peru between 1952 and 1964 are presented. In this series it is seen that retinoblastoma is the third most frequent neoplasm affecting children under fifteen years of age. The disease was bilateral in 29.4 per cent of the cases. In 70 per cent of the cases the disease had reached stage III and IV, according to the classification proposed by Knapp, at the time that the patients appeared at the Instituto. In unilateral retinoblastoma, 90.9 per cent of the patients with lesions of stage I and II survived for five years, in patients with stage III lesions the rate is 15 per cent, and the over-all five year survival rate is 30.2 per cent. In cases of bilateral retinoblastoma 16.6 per cent survived for five years. The use of cyclophosphamide in patients with an advanced stage of disease prolongs life considerably. © 1967.