Background: Bladder health in women and girls is poorly understood, in part, due to absence of a definition for clinical or research purposes. This article describes the process used by a National Institutes of Health funded transdisciplinary research team (The Prevention of Lower Urinary Tract Symptoms [PLUS] Consortium) to develop a definition of bladder health. Methods: The PLUS Consortium identified currently accepted lower urinary tract symptoms (LUTS) and outlined elements of storage and emptying functions of the bladder. Consistent with the World Health Organization's definition of health, PLUS concluded that absence of LUTS was insufficient and emphasizes the bladder's ability to adapt to short-term physical, psychosocial, and environmental challenges for the final definition. Definitions for subjective experiences and objective measures of bladder dysfunction and health were drafted. An additional bioregulatory function to protect against infection, neoplasia, chemical, or biologic threats was proposed. Results: PLUS proposes that bladder health be defined as: "A complete state of physical, mental, and social well-being related to bladder function and not merely the absence of LUTS. Healthy bladder function permits daily activities, adapts to short-term physical or environmental stressors, and allows optimal well-being (e.g., travel, exercise, social, occupational, or other activities)." Definitions for each element of bladder function are reported with suggested subjective and objective measures. Conclusions: PLUS used a comprehensive transdisciplinary process to develop a bladder health definition. This will inform instrument development for evaluation of bladder health promotion and prevention of LUTS in research and public health initiatives.