Cyclophosphamide (CYP) treatment induces chemical cystitis leading to bladder overactivity (OAB) in animals and humans. There is a great number of OAB models evaluations, which consider the bladder histology, as well as alterations in neurochemical, electrophysiological properties of bladder afferent neurons and reflex arcs activity in the spinal cord. However there are no data differentiating cystometrically acute and chronic models of OAB induced by CYP under urethane anaesthesia. The aim of this study was to investigate the influence of acute and chronic models of CYP-induced cystitis on urinary bladder motor activity in rats.