Objectives: Urinary incontinence is a hygienic and socially distressing problem for affected people and causes high healthcare costs. Objective standardized noninvasive quantification of urinary incontinence is highly important and, in addition, enables control of therapeutic efficacy. The aim of this prospective study was to evaluate the feasibility, accuracy and reproducibility of a standardized 20-min pad test to measure urinary incontinence after radical prostatectomy in comparison to the 1-hour pad-weighing test recommended by the International Continence Society (ICS). Methods: We applied a standardized questionnaire, the ICS 1-hour pad test and a simplified 20-min pad test to evaluate subjective and objective post-prostatectomy urinary incontinence in 56 men. Results: The technical feasibility of the 20-min pad test was excellent; the results correlated significantly with both the self-assessment via questionnaire (r = 0.63; p < 0.001) and the 1-hour pad test (ICS; r = 0.66; p < 0.001). Moreover, it was highly reliable (r = 0.74; p < 0.0005) with excellent patient acceptance. Conclusions: The 20-min pad test qualified as a reliable, cost-effective and noninvasive tool which can easily be applied in urologic or physiotherapeutic practice to assess post-prostatectomy urinary incontinence and to evaluate the success of therapeutic approaches.