Purpose: To investigate the effect of vancomycin added to the intraocular irrigation solution to prevent anterior chamber contamination during phacoemulsification.Setting: Centre Hospitalier, Villeneuve-Saint-Georges, France.Methods: A group of 372 patients having cataract extraction by phacoemulsification was divided into two consecutive, nonrandomized groups. The first group (n = 190) was a control; there was no antibiotic in the irrigation solution. The second group (n = 182) received vancomycin in the irrigation solution. Intraocular fluid was aspirated at the end of surgery and injected into a blood culture bottle to evaluate bacterial contamination of the anterior chamber.Results: There was no between-group difference in bacterial intraocular contamination. Eight samples in the first group were contaminated and nine in the second group. All contaminants were gram-positive vancomycin-sensitive organisms.Conclusions: Adding vancomycin to the intraocular irrigation solution during cataract surgery had no effect on the occurrence of intraocular contamination as evaluated by anterior chamber taps.