Purpose: To report a case of bilateral vitritis originated from Primary Central Nervous System Lymphoma. Diagnosis was made from a careful history taking and confirmed with vitrectomy. Case report: 65-year-old Vietnamese male had one month of progressive blurred vision in both eyes without other eye complaint. History revealed that about one year previously, he was diagnosed with primary diffuse large B cell lymphoma. He was treated with chemotherapy of Methotrexate 3.5 g/m2 and cytarabine 2 mg/m2, and a whole brain radiation therapy. There was a complete remission after the therapy. Fundus of both eyes was partly obscured by cells mainly in the posterior vitreous. Sequential bilateral vitrectomies were done on 5/1/17 and 7/17/17 without complication. The vitreous sample from the first eye having vitrectomy was sent for study which demonstrated large B cell lymphoma. Post-operative vision improved to 20/25 both eye without the complaint of hazy vision. Conclusion: Good history taking assisted in the diagnosis of intraocular lymphoma in this case with bilateral vitritis. However, bilateral vitrectomy restored the vision and further confirmed the diagnosis of lymphoma for future follow up care.