Six patients (aged 8 to 75 years) who were operated upon during the same day developed bacterial endophthalmitis on the following day; seven eyes were affected. Two patients had intracapsular cataract extraction, one extracapsular lens extraction, two extracapsular cataract extraction with intraocular lens implantation and one repair of bilateral scleral or corneoscleral perforations. Vitreous cultures taken from six eyes were positive for an Enterobacter sp. Despite antibiotic treatment systemically, subconjunctivally and intravitreally, four eyes had to be eviscerated, while two eyes showed evidence of shrinkage (phthisis); only one eye retained useful vision ( 9 10). Cotton swabs used during surgery, prepared manually from cotton wool moistened with saline, were identified as the source of infection; the batch had not been subjected to the prescribed autoclaving process. The importance of proper sterile procedures in association with surgery is emphasized. © 1994.