The assessment of lower urinary tract symptoms is an essential component of the evaluation of men with benign prostatic disease in clinical practice and research. Symptom evaluation is necessary for the formal evaluation of the effectiveness of treatments in randomized controlled trials and in the assessment of outcome in individuals, and can also be useful in determining the numbers of individuals in the community who might potentially require or benefit most from treatment. Increasingly, symptom assessments are being undertaken using a small number of questionnaires that are self-completed by patients and have been tested for validity and reliability.