Interstitial cystitis (IC) is a chronic inflammatory condition of the bladder wall, characterized by urinary frequency and urgency, and severe suprapubic and/or pelvic pain. Symptoms of IC resemble those of ordinary urinary tract infections. However, standard urine cultures are negative and antibiotic therapy offers no relief. Recent research indicates that IC may be much more common than was previously thought, affecting over 700,000 people in the US. More than 90% of those affected are women, many of whose lives are thoroughly disrupted by severe pain. Long overlooked and misdiagnosed, IC is only now beginning to be understood. Although there is no specific diagnostic test or marker for IC and no uniformly effective treatment, little more than a decade of research has yielded promising results. New diagnostic tests are currently being developed and new therapeutic modalities are in clinical trials. While science searches for answers to this devastating disease, patients living with pain deserve relief.