PURPOSE: We investigated whether same session repeat urodynamic investigations are needed in patients with neurogenic lower urinary tract dysfunction. MATERIALS AND METHODS: A consecutive series of 226 patients with neurogenic lower urinary tract dysfunction who underwent same session repeat urodynamic investigation was prospectively investigated at a single university spinal cord injury center. Urodynamics were done according to the good urodynamic practices recommended by the International Continence Society. All 226 patients underwent same session repeat consecutive filling cystometry and 88 also underwent pressure flow studies if they could void spontaneously. Repeatability of the 2 measurements was assessed using the Bland and Altman 95% limits of agreement, and the κ statistic. RESULTS: Mean age of the 226 patients enrolled was 52 years (range 18 to 90). Of the patients 94 (42%) were women and 132 were (58%) men. Detrusor overactivity repeatability was excellent between the 2 urodynamic investigations (κ=0.87, 95% CI 0.80-0.94). For all other urodynamic parameters assessed there were wide 95% limits of agreement for differences in the parameters, indicating poor repeatability. CONCLUSIONS: In same session repeat urodynamic investigations of patients with neurogenic lower urinary tract dysfunction detrusor overactivity demonstrates excellent repeatability but all other urodynamic parameters show insufficient agreement. Thus, we strongly recommend that clinical decision making not be based on a single urodynamic investigation since repeat measurements may yield completely different results.