This study evaluated the clinical features and treatment outcome of 15 patients with primary intraocular lymphoma. There were nine females, with a median age of 68 years. Thirteen patients presented with bilateral lesions and median time from the onset of symptoms to diagnosis was 12 months. All but one showed the B-cell phenotype. All patients received radiation therapy (RT) with a median of 41 Gy and 10 were administered chemotherapy as well. Three patients were treated with high-dose methotrexate and nine received prophylactic cranial irradiation (PCI) with a median of 30.6 Gy. Thirteen patients obtained a complete remission. The 2-year overall and disease free survival were 74% and 58%, respectively. Although only one patient experienced local recurrence, PCI did not prevent intracranial recurrence. One patient developed a grade 3 cognitive disturbance. It was concluded that ocular RT was effective to control primary lesions. However, some modifications are indispensable to improve outcomes.