: Our purpose is to report a patient with primary unilateral ciliary body marginal zone lymphoma who initially presented with hemorrhagic hypopyon. Methods: Retrospective review of the clinical, imaging, and immunohistopathological features of the case was performed. : A 59-year-old man was referred with right anterior uveitis of unknown etiology which was unresponsive to systemic treatment. Slit-lamp biomicroscopy showed normotensive hemorrhagic hypopyon in that eye. Anterior segment ultrasound biomicroscopy revealed an iridociliary mass lesion. Because an anterior chamber paracentesis was noncontributory, a diagnostic cyclectomy was performed. Histopathological evaluation showed that the neoplastic cells were positive for CD20, lambda light chain, and BCL 2. BCL 6, CD10, CD5, SOX11, kappa, and Cyclin D1 stains were negative. The final diagnosis was extranodal marginal zone lymphoma of the ciliary body. : Although rare, ciliary lymphoma may be a cause of intractable anterior uveitis. Repeat biopsies could be carried out when there is a high level of clinical suspicion.