Purpose: To evaluate changes in nocturia after surgical correction of obstructive sleep apnea (OSA). Methods: A total of 66 patients were included in the present study. All had been diagnosed with OSA syndrome by polysomnography and underwent uvulopalatopharyngoplasty (UPPP). Preoperative and postoperative lower urinary tract symptoms (LUTS), quality of life (QoL), and nocturia episodes were evaluated using the International Prostate Symptom Score (IPSS) and overactive bladder symptom score (OABSS) questionnaires. Three months postoperatively, telephone interviews were performed to determine the success of surgery, current LUTS, and nocturia episodes. Patients were divided into surgical success and failure groups. Surgical success was defined as snoring decrease more than 50% based on the patient's subjective judgment. Results: The response rate was 56% and success rate was 73%. In all patients, nocturia episodes significantly decreased from 1.7 +/- 1.1 to 0.8 +/- 1.2 (P = 0.002). Mean IPSS score, OABSS score, and QoL scores were also significantly improved. The success group showed a significant decrease in nocturia episodes, and total IPSS, OABSS, and QoL scores. However, the failure group did not show significant changes in all parameters. Conclusions: OSA correction improved nocturia as well as other LUTS. These improvements were not observed in the failure group. This study shows that OSA is a cause of nocturia and that other LUTS and nocturia can be improved by surgical correction of OSA.