Purpose: A randomized, double-masked study of 317 patients was conducted to determine if the incidence of postcataract ptosis is greater with retrobulbar or twoinjection peribulbar injection anesthesia. Methods: Surgery consisted of a planned extracapsular extraction with posterior chamber lens implantation, and no superior rectus bridle suture was used. Ptosis was quantitatively documented preoperatively and postoperatively at 1, 2, 5, and 90 days by the surgeon, photographically at 90 days by a masked observer, and subjectively by the patients. Postcataract ptosis was defined as a drop in the lid margin of 2 mm or greater after correcting for any change in the fellow eye. Results: The incidence of ptosis at 90 days in patients given peribulbar anesthesia was 5.8% and in patients given retrobulbar anesthesia 5.5%, and this difference was not statistically significant (P = 0.90). Eighteen percent of patients in both groups reported a change in the appearance of their eyelids. There was a moderate, positive correlation among patients who reported a change in their lid position and objective measurements of ptosis. Preoperative clinical measurements of vertical lid fissure width and levator function, and the appearance of the lid crease or superior sulcus were not predictive for the development of postoperative ptosis at 90 days; the best predictor was the presence of ptosis in the immediate postoperative period. Conclusions: The incidence of postcataract ptosis is the same whether two injection peribulbar or retrobulbar anesthesia is used.