A 55-year-old female presented with bilateral progressive retinal vasculitis. She was on systemic and intravitreal steroids on the basis of uveitis work-up result (negative result including rapid plasma reagin), but her visual acuity continued to deteriorate to light perception only. Ocular examination showed retinal vasculitis, multiple yellow placoid lesions and severe macula edema in both eyes. Repeated work-up revealed positivity of fluorescent treponemal antibody-absorption in serum and subsequently in cerebrospinal fluid. Ocular syphilis was diagnosed. And intravenous penicillin G resulted in rapid resolution of vasculitis and macular edema. To avoid delay in the diagnosis of ocular syphilis, high index of suspicion and repeating serological tests (including both treponemal and non-treponemal tests) are warranted.