The aim of this study was to determine the effect of memantine on overactive detrusor (OAD) 15 days after spinal cord injury (SCI) in rats. Twenty-eight adult Wistar rats were used in this study. Fourteen animals served as normal controls, while 14 underwent spinal cord transection (clip compression technique) at the 10(th) thoracic vertebra. Fifteen days after SCI, all animals underwent urodynamic testing to confirm OAD. Memantine (16 mg/kg) was injected intraperitoneally into rats with SO and OAD. Parameters measured included voiding volume, micturition pressure, resting bladder pressure, the period between micturitions and the maximum pressure of the OAD during the filling period. Results have showed that OAD developed in 8/14 animals (57.1%). OAD was resolved in 5/8 (62.5%) of these animals after memantine administration. Resting bladder pressure was significantly different in dependent groups (p < 0.05). Micturition pressure increased after SCI but decreased in rats with SCI after memantine injection. However, the period between micturitions was prolonged in both SCI and memantine groups, compared with normal rats. These results show that memantine could be useful for treating neurogenic OAD after SCI by modulating the micturition reflex pathway. Memantine may also provide an alternative treatment option for OAD in the future.