Purpose: To determine the effect of anterior capsule polishing (APC) on the rate of posterior capsule opacification (PCO) as assessed by the need for laser posterior capsulotomy. Setting: University-based clinical practice, Jules Stein Eye Institute, Los Angles, California, USA. Methods: This study involved a retrospective review of eyes that underwent phacoemulsification and intraocular lens implantation between September 1991 and June 1999. Lens epithelial cells in the 763 study eyes were mechanically debrided or polished from the inside surface of the anterior capsules using a pair of Shepherd-Rentsch (Morning STAAR Inc.) capsule polishers. The 484 control eyes that had surgery earlier in the series were not polished. The rate of laser capsulotomy in the ACP and the non-ACP groups was compared using a Kaplan-Meier survival analysis. Multivariate regression was performed to determine if variables other than ACP influenced the need for laser posterior capsulotomy. Results: We identified 763 eyes that had ACP and 484 that did not. At the 24-month follow-up interval, 26.6% of the eyes in the ACP group had received a capsulotomy versus 19.50% in the non-APC. Next, a separate study was done using only one eye per patient, taking the patient as the unit of analysis. Again the capsulotomy rate was higher in the ACP group compared to the non-ACP (1.02 per 100 person-months of follow-up vs. 0.74 per 100 person-months of follow-up). Finally, a third Kaplan-Meier analysis was done on 52 patients that had one eye treated with the ACP procedure and the other eye with the non-ACP procedure. Although the log-rank test showed the statistical significant of this analysis to be borderline, the results again favored the non-ACP group with a lower capsulotomy rate. Multivariate analysis showed very similar results to the above univariate studies. The mean time to capsulotomy was 46 months for the polished group and 70 months for the unpolished group. The severity of cataract (p = 0.46) and the type of haptics (p = 0.86) did not influence the rate of capsulotomy. Plate haptic IOLS had a higher rate of capsulotomy than loop haptic IOLS (p = 0.001). Conclusions: Polishing of the anterior capsule with Shepherd-Rentsch polishers may unexpectedly increase the rate of posterior capsule opacification in eyes with round-edge silicone lenses.