Interstitial cystitis (IC) is a disease of the urinary bladder with lower urinary tract symptoms such as urinary frequency, bladder hypersensitivity and/or bladder pain and resultant serious impairment of quality of life. In Japan, assuming that IC is very rare, research activity and medical care of IC have been sparse until 2001, when the Society of Interstitial Cystitis of Japan (SICJ) and a patient support group were founded.(1,2) Subsequently the International Consultation on Interstitial Cystitis Japan (ICICJ) was held in Kyoto in 2003.(3) On the other hand, the etiology of IC has not been well clarified, which complicates its diagnosis and treatment at clinical settings. We have thus developed the Japanese Clinical Guideline,(4) which is targeted at healthcare professionals including specialists in urology and women's health care who may engage in the diagnosis and treatment of IC. This article is the English translation of a shortened version of the Guideline for convenience of readers worldwide.