Brucellosis may be associated with a wide range of ophthalmic manifestations including endophthalmitis, which is a sight-threatening condition that needs to be rapidly recognized and treated to avoid permanent visual loss. A 26-year-old female with a 6-month history of vision loss in the left eye was treated with high dose systemic corticosteroids and azathioprine with an initial misdiagnosis elsewhere. A dense vitreous haze with opacities at the posterior hyaloid and a wide area of retinochoroiditis led to the diagnosis of endogenous endophthalmitis at presentation to us. The vitreous sample and blood cultures demonstrated growth of Brucella melitensis. She received 6 months of systemic antibiotherapy, which resulted in resolution of inflammation; however, visual acuity remained poor due to irreversible damage. Infectious etiology, including brucellosis in endemic countries, has to be considered in the differential diagnosis before administering immunomodulatory therapy in patients with panuveitis of unknown origin.