Interstitial cystitis is a disease characterized by pain occurring as the urinary bladder is gradually filling up. Its pathophysiology is unknown. The cause could be either a membrane permeability disorder, a mast cell disturbance in the bladder wall, or an autoimmune process involving the bladder. The diagnosis is essentially clinical but endoscopies and biopsies are required to rule out vesical cancers. Treatments is difficult and based on a combination of sanitary and dietary regimens, as well as drugs administered orally or infused within the bladder. Surgical treatment must remain exceptional.