The high incidence of rubeosis iridis accompanying retinoblastoma has been reaffired. Factor common to ocular tumors in general and retinoblastoma, as well as reactions to retioblastoma that have some contributory effect upon vascularization of the iris have been studied and complied. No single causative factor emerged, although tumor necrosis obviously played an important role. To a lesser extent, the site, location, and intraocular extension bore some relationship to neovascularization. That iris neovascularization carries a more grave prognosis, until now only a clinical impression, was definitely confirmed. Clinicians, therefore, studying patients with retinoblastoma would be well advised to pay more attention to the iris and anterior segment since recognition of changes leads to more timely and knowledgeable management. It was hoped that increased recognition of rubeosis would differentiate between eyes with retinoblastoma and those with pseudoglioma; however, an equally high incidence of neovascularization accompanied certain pseudogliomas. In both studies, as is often the case, numerous interesting observations were made; several with clinical implications. Finally, a frequently associated glaucoma, suggested by the anterior segment histologic features, went urecognized and unrecorded in these patients.