Objectives. To outline a systematic approach to the evaluation, diagnosis and treatment of interstitial cystitis (IC). Methods. A review of the literature as well as of our experience. Results. The exclusion criteria for the research definition of IC can be used as guides when obtaining the history, physical examination, laboratory workup, and finally urodynamics and cystoscopy/hydrodistension under anesthesia. Once the diagnosis is established, patients who are still symptomatic after hydrodistension are treated initially with oral medications. Those who do not respond to oral therapy are given intravesical therapy. Patients whose symptoms are refractory to both routes can be considered for a TENS unit, experimental oral therapies, chronic pain control with opioids, or, as a last resort, surgery to create a urinary diversion. Conclusion. As IC is a diagnosis of exclusion, the evaluation remains one of ruling out other disorders that produce similar symptoms in patients whose history suggests IC. Until the etiology and pathogenesis of IC are identified, specific therapy is not possible. However, symptomatic treatments are helpful in the majority of patients. (C) 1997 by Elsevier Science Inc.