PURPOSE We assessed urodynamic parameters within the first 40 days after spinal cord injury (SCI) investigating whether the detrusor is acontractile during the acute phase of SCI. PATIENTS AND METHODS We performed a prospective cohort study including 54 patients with neurogenic lower urinary tract dysfunction (NLUTD) due to acute SCI undergoing urodynamic investigation (UDI) within the first 40 days after injury at a single university SCI center. RESULTS and Limitations: Of the 54 patients, UDI revealed an acontractile detrusor in only 20 (37%) but unfavorable urodynamic parameters in a total of 34 (63%) patients. Detrusor overactivity was found in 32 patients, detrusor sphincter dyssynergia in 25, maximum storage detrusor pressure >40cmH2O in 17, vesico-uretero-renal reflux in 3 and low bladder compliance (<20mL/cmH2O) in 1 patient (more than one unfavorable urodynamic parameter possible). CONCLUSIONS In contrast to the common notion of an acontractile detrusor during acute SCI, almost two-thirds of our patients showed unfavorable urodynamic parameters within the first 40 days after SCI. Considering that early treatment of NLUTD in patients with acute SCI might improve long-term urological outcome, UDI should be performed timely to optimize patient-tailored therapy.