Interstitial cystitis (IC) is a disorder that is difficult to diagnose and is thought to be uncommon in children. We report the first case of IC coexisting with vulvar vestibulitis in a 4-year-old girl. She presented with urinary symptoms and pelvic and vulvar pain. Cystoscopic and histological investigation confirmed interstitial cystitis and vulvar vestibulitis. Gynecologists are often called upon to deal with symptoms referable to the genital tract. It is important to always include interstitial cystitis in the differential diagnosis of urinary symptoms associated with pelvic pain.