Purpose: To evaluate the clinical effectiveness and safety of the erbium:YAG (Er:YAG) laser for cataract extraction surgery. Setting: Visual Sciences Institute, Madrid, Spain. Methods: In this prospective randomized study, 65 eyes of 50 patients scheduled for cataract extraction were divided into 2 groups based on the type of lens emulsification: Er:YAG laser (40 eyes) or ultrasound (US) (25 eyes). The laser procedure was converted to the US technique in cases with potential complications. All patients received a foldable posterior chamber intraocular lens. A complete ophthalmologic examination including topographic analysis, pachymetry, and endothelial cell count was performed preoperatively and 1 day, 2 weeks, and 1, 3, 6, and 12 months postoperatively. All patients had fluorescein angiography at 1 month to rule out subclinical cystoid macular edema (CME). Results: There were no significant differences between the techniques in any parameter at any time. In both groups, visual acuity significantly increased and endothelial cell count significantly decreased postoperatively ( P < .01). The only serious complication was subclinical CME in 2 patients 1 month after the laser procedure. Conclusions: Emulsification of the lens using the Er:YAG laser was effective for performing small incision cataract surgery in eyes with soft and medium nuclei. The small ablation zones created can help prevent damage to surrounding ocular structures. The Er:YAG technique used less ablation energy than US emulsification and did not result in thermal injury.