Background Intraocular lymphoma (IOL) is a rare malignant lymphoma that most closely resemblesa diffuse large B-cell lymphoma, and it is a subtype of primary central nervous systemlymphoma (PCNSL). IOL is located inside the eye in the retina, uvea, and/or optic nerve. We retrospectively analyzed IOL patient data to identify treatment patterns and survivalrates in Korea. Methods Cytological confirmation for a diagnosis of IOL was performed for all patients. The clinicaldata collected from medical records included Ann Arbor stage, International Prognostic Index, performance status, date of diagnosis, treatment modality and response, date of relapse, and date of last follow-up. Results Twenty patients who were diagnosed with IOL, between December 2007 and June 2014 at multiple centers in Korea, were included in the analysis. Four patients were diagnosed with IOL alone, not involving the CNS. Two patients with isolated IOL later developed PCNSL. Nine patients developed CNS lesions before the onset of ocular lymphoma. Fivepatients had simultaneous onset in the eye and CNS. Twelve patients were treated by intravitreal injection of methotrexate for IOL. The median progression-free survival (PFS) forpatients was 19.7 months (95% CI, 8.7-30.7 mo). The estimated 3-year overall survival(OS) for all patients was 75.1%. Conclusion Treatment for IOL patients included radiotherapy and intraocular chemotherapy. IOL patients showed favorable PFS and OS. These patients would require long-term follow-upto identify relapse and adverse effects of radiotherapy or intraocular chemotherapy.