The International Continence Society established a committee in 1973 to standardize terminology for lower urinary tract function. Five reports from this committee have been published, with the fifth being an internal document. This monograph revises and extends these reports to provide standardized guidelines for urodynamic studies. These standards aim to facilitate comparison of results among investigators, both in human and animal studies. When using animal studies, the type of anaesthesia should be stated. Acknowledgment of these standards in publications should be indicated in a footnote. Urodynamic studies assess urinary tract function and dysfunction using various methods. Factors like morphology, physiology, biochemistry, and hydrodynamics affect urine transport and storage. Radiographic visualization is a useful adjunct to conventional urodynamics. Clinical assessment of lower urinary tract dysfunction includes a detailed history, frequency/volume chart, and physical examination. The history should cover neurological and congenital abnormalities, previous infections, surgery, and other relevant factors. The urinary history should include symptoms related to storage and evacuation. The frequency/volume chart records fluid intake and urine output over 24 hours, providing objective data on voiding frequency, volume, and episodes of urgency or leakage. Physical examination includes urological and gynaecological exams, perineal sensation, reflexes, and anal sphincter tone. Cystometry measures the pressure/volume relationship of the bladder. It involves measuring residual urine, bladder capacity, compliance, and detrusor activity. Parameters such as access method, fluid medium, temperature, patient position, and filling rate should be specified. The filling rate is categorized as slow, medium, or rapid. Techniques include fluid-filled catheters, transducers, and measuring equipment. Definitions include intravesical pressure, abdominal pressure, detrusor pressure, bladder sensation, capacity, and compliance. Urethral pressure measurement assesses the urethra's ability to prevent leakage, with measurements taken at rest, during coughing, and during voiding.The International Continence Society established a committee in 1973 to standardize terminology for lower urinary tract function. Five reports from this committee have been published, with the fifth being an internal document. This monograph revises and extends these reports to provide standardized guidelines for urodynamic studies. These standards aim to facilitate comparison of results among investigators, both in human and animal studies. When using animal studies, the type of anaesthesia should be stated. Acknowledgment of these standards in publications should be indicated in a footnote. Urodynamic studies assess urinary tract function and dysfunction using various methods. Factors like morphology, physiology, biochemistry, and hydrodynamics affect urine transport and storage. Radiographic visualization is a useful adjunct to conventional urodynamics. Clinical assessment of lower urinary tract dysfunction includes a detailed history, frequency/volume chart, and physical examination. The history should cover neurological and congenital abnormalities, previous infections, surgery, and other relevant factors. The urinary history should include symptoms related to storage and evacuation. The frequency/volume chart records fluid intake and urine output over 24 hours, providing objective data on voiding frequency, volume, and episodes of urgency or leakage. Physical examination includes urological and gynaecological exams, perineal sensation, reflexes, and anal sphincter tone. Cystometry measures the pressure/volume relationship of the bladder. It involves measuring residual urine, bladder capacity, compliance, and detrusor activity. Parameters such as access method, fluid medium, temperature, patient position, and filling rate should be specified. The filling rate is categorized as slow, medium, or rapid. Techniques include fluid-filled catheters, transducers, and measuring equipment. Definitions include intravesical pressure, abdominal pressure, detrusor pressure, bladder sensation, capacity, and compliance. Urethral pressure measurement assesses the urethra's ability to prevent leakage, with measurements taken at rest, during coughing, and during voiding.