We present two cases of Propionibacterium acnes endophthalmitis that confirm the association of this organism with a delayed onset and chronic and indolent intraocular inflammation following extracapsular cataract extraction with posterior chamber intraocular lens implantation. The clinical, microbiologic, and histopathologic features of these cases suggest that the organism can be sequestered in the capsular bag, which may make this entity difficult to diagnose. We conclude that complete capsulectomy may be required if inflammation persists after conventional treatment for endophthalmitis, which may include pars plana vitrectomy, partial capsulectomy, and antibiotic therapy. Sterile postoperative uveitis is a diagnosis of exclusion. We stress the importance of appropriate microbiologic investigation in all cases of postsurgical inflammation, even if the onset is delayed until several months after surgery.