Introduction: The prevalence of obesity has increased all over the world and it is closely correlated to multiple medical comorbidities. The aim of this study is to compare dexmedetomidine sedation and remifentanil sedation with respect to safety and effectiveness for obese patients undergoing cataract surgery with peribulbar anesthesia. Methods: Eighty ASA II-III patients scheduled for cataract surgery were randomly assigned to receive an infusion of either 0.4 mcg/kg/min dexmedetomidin or 0.05 mcg/kg/min remifentanil. Body mass indexes of all patients were between 30-40 kg/m(2). Infusion drug doses were applied according to patients' ideal body weights. Primary outcome was to assess respiratory depression and analgesia by peripheral oxygen saturation and bispectral index scores respectively. Results: There was no significant deifference in demographic variables of the patients. In the first 25 minutes peripheral oxygen saturation levels were higher in dexmedetomidine group and it was higher in remifentanil group after 35th minute. BIS scores were lower in dexmedetomidine group throughout the operation. Conclusion: Sedation for obese patients has several clinical challenges. Both dexmedetomidine and remifentanil can be accepted as appropriate drug preferences for sedation of obese patients, while dexmedetomidine provided a safer and more effective analgesia in our study.