Cancer deaths among close relatives of 19 patients with bilateral retinoblastoma were reviewed. Altogether 18 deaths of nonocular cancer were found in 5 families. These constitute 5% of the entire material of 365 relatives. The main types of cancer were stomach (6 cases), bronchial (3 cases), urinary bladder carcinoma (2 cases), as well as 2 cases of reticulosarcoma and 1 of leukemia. The retinoblastoma gene may also be associated with higher incidence of cancer in families of retinoblastoma patients.