Purpose. To investigate the occurrence of contaminated cultures of vitreous specimens from non-infected eyes obtained using anaerobic techniques employed for endophthalmitis.Methods. Vitreous specimens were obtained using meticulous sterile techniques employed for endophthalmitis from seventeen patients undergoing pars plana vitrectomy for non-infective indications: vitreous hemorrhage (12 eyes), retinal detachment (3), Coat's disease (1), and congenital dislocated lens (1). Vitreous specimens were inoculated in the operating room onto an anaerobic blood agar plate and into thioglycolate broth. Bacterial growth occurring before 10 days was considered positive.Results. Three organisms were isolated from three separate eyes. One colony of Staphylococcus species was isolated on an anaerobic blood agar plate on day 3. A single colony ofPropionibac-terium acnesgrew on an anaerobic blood agar plate on day 6. Alpha-hemolytic streptococci grew from thioglycolate broth on day 10.Conclusions. Growth as detected in this study might represent contamination rather than an infecting organism in an eye suspected of having endophthalmitis.