In our department 14 patients with primary carcinoma in situ of the bladder were treated. Thirteen patients were male and 1 patient was female. Most of the patients complained of irritative vesical symptoms such as painful urination and/or pollakisuria. Cystoscopic examination revealed no overt tumor but some abnormal findings like localized or diffuse hyperemia or fine granular changes were noted. In 4 patients, total cystectomy was performed primarily and 10 other patients were treated at first with intravesical chemotherapy or intravesical BCG. Five of those 10 patients (50%) developed invasive cancer and total cystectomy was performed secondarily in them. Invasive cancer occurred in the bladder wall in 2 patients, in the prostate in 2 patients and in both bladder and prostate in 1 patient. Five-year and 10-year survival rates of 14 patients in this study were 66.7% and 44.4%, respectively.