An 80-year-old woman presented with right endophthalmitis. characterized by chalky white deposits covering her posterior capsule. This occurred 17 months after uncomplicated right cataract surgery. A three-port pars plana vitrectomy and partial posterior capsulectomy isolated Bacillus circulans, and the patient made a rapid and full recovery on topical cephalothin and prednisolone acetate 1%. The case demonstrates that, unlike endophthalmitis due to other Bacillus spp., B. circulans endophthalmitis does not necessarily follow a fulminant course. It is the first report describing a subacute presentation, and response to posterior capsulectomy and simple antibiotic therapy. it is also the first description of B, circulans causing while plaques in the posterior capsule, a finding characteristic of chronic endophthalmitis and previously considered pathognomonic of Proprionibacterium acnes endophthalmitis.