AIM: To investigate the clinical manifestations, diagnostic approaches, treatments, and outcomes of intraocular lymphoma. METHODS: In this retrospective study, 16 patients (28 eyes) with intraocular lymphoma were recruited in the Department of Ophthalmology, Peking Union Medical College Hospital, from 2004 to 2019. All patients underwent comprehensive ophthalmic examinations. Vitreous specimens of 13 patients were sent for cytopathology examination and other adjunctive diagnostic procedures. Three patients were diagnosed with intraocular lymphoma according to analysis of the histopathological results of systemic lymphoma by one clinician. Twenty-three eyes were treated with intravitreal administration of methotrexate, 4 eyes could not receive ocular treatment due to life-threatening lymphoma, and 1 eye did not require ocular treatment because the fundus lesions regressed after systematic chemotherapy. RESULTS: In 28 eyes, 25 eyes were diagnosed with vitreoretinal lymphoma, and 3 eyes were diagnosed with ciliary body lymphoma, all of which were non-Hodgkin diffuse large B cell lymphomas. The final visual acuity improved in 15 eyes (54%), remained unchanged in 5 eyes (18%), and decreased in 8 eyes (29%). Anterior segment inflammation disappeared or reduced in 8 and 5 eyes, respectively; and 15 eyes had no anterior segment reaction. Twenty eyes had mild vitreous opacity, 1 eye had mild vitritis, and 7 eyes had pars plana vitrectomy combined with silicone oil tamponade. Fundus lesions disappeared in 9 eyes and were relieved in 5 eyes; 4 eyes showed no changes, and the remaining 10 eyes' fundus were normal. CONCLUSION: The clinical manifestations of intraocular lymphoma are diverse, and the misdiagnosis rate is high. Cytopathological analysis of vitreous is one of the gold standards for the diagnosis. Immunohistochemistry, gene rearrangement and flow cytometric immunophenotypic analysis can improve the diagnostic rate. Ocular chemotherapy or radiotherapy regimens may preserve visual acuity, and a multidisciplinary team can provide individualized treatment for the patients.