The aim of the study was to examine how interstitial cystitis (IC) initiates its clinical course, which changes as the disease progresses from the initial phase to its full clinical manifestation. Patients diagnosed with IC between 1998 and 2003 in our department were evaluated and reviewed regularly. The exact onset of urinary symptoms was recorded. Diagnosis of IC was made by National Institute of Diabetes and Digestive and Kidney Disease (NIDDK) criteria when clinical suspicion of IC was present. The study group included 30 female patients who were 27-69 years old when diagnosis was made. Mean age was 46.7. Seventy percent of patients had only one symptom at onset. The most frequent initial diagnosis was urinary tract infection (UTI). A condition of recurrent bacterial UTIs, with subsequent persistence of symptoms and negative cultures, could be detected as a harbinger of IC in 60% of our patient group. IC may manifest initially with a single symptom in its early stage, when diagnosis is perhaps less easy, but adequate and effective treatment can still be offered to the patient.