Even though interstitial cystitis (IC) is a rare syndrome it is more prevalent than is generally thought. The majority of patients remain undiagnosed and receive no treatment to ease their discomfort. Clinical diagnosis is based on symptoms (urinary frequency, urgency, nocturia, dyspareunia and lower abdominal pain which increases as the bladder fills). There are no specific signs or diagnostic criteria. Foremost for the diagnosis is the use of hydrodistention during cystoscopy, after which the physician will look for the presence of petechial haemorrhages and/or for Hunner's ulcers (the histological finding will show an increased number of mast cells). In urodynamic studies, the activation of sensory nerves causes painful feelings of urinary urgency without simultaneous bladder contractions at bladder filling of less than 150 ml. The need for patient education and support is great. Amitriptyline should be tried as the first line drug.