PURPOSE: To compare the cataract surgery related complications between patients with and without tamsulosin treatment. DESIGN: A nationwide retrospective case-control study. METHODS: Patients who had undergone cataract surgery were identified using the International Classification of Disease, Ninth Revision, Clinical Modification from a nationally representative dataset of 1 million people selected from the Taiwan National Health Insurance Research Database in 2000. Patients preoperatively treated with alpha(1)-blockers before cataract surgery were the treated group, and age-, sex-, and year of surgery matched patients not preoperatively treated with alpha(1)-blockers were the control group. Patients treated with tamsulosin underwent subgroup analysis. A conditional logistic regression model was used to estimate surgery-related complications and interesting variables. The main outcome measures are cataract surgery related complications. RESULTS: A total of 4474 treated patients and 4474 controls were analyzed. The percentage of cataract surgery related complications was 8.61% in the treated group and 8% in the control group (not significantly different). However, wound dehiscence was 3.81 times higher (95% confidence interval: 1.24-11.67, P = .0194) in the tamsulosin-treated group. CONCLUSIONS: Patients treated with tamsulosin have a higher risk of wound dehiscence after cataract surgery. Carefully taking a history of tamsulosin use before cataract surgery is advised so that some strategies can be used to prevent complications and additional costs. (C) 2014 by Elsevier Inc. All rights reserved.