Validation of reliable symptom scores for evaluation of patients with benign prostatic hyperplasia (BPH) provides reproducible tools for patient follow-up and for use in therapeutic trials. The International Prostate Symptom Score (I-PSS) is currently the reference questionnaire for evaluation of patients with BPH. Some of the symptoms of BPH are particularly disabling, especially nocturia. Evaluation of nocturia is essential in view of its direct impact on the patient's daily life. The I-PSS devotes a single item to nocturia. The N-QoL questionnaire appears to be more suitable to measure the impact of nocturia on quality of life, as it investigates the concepts of sleep, vitality, discomfort and overall quality of life.