Screening for cervical carcinoma by cervicovaginal cytology has led to a marked reduction in the incidence of and mortality from this tumor over the last 50 years in essentially all countries with a functioning screening program. It is the most successful cancer prevention program of all times. Consequently, approximately 80% of the current incidence of and mortality from this disease occurs in geographic areas of underserved and underscreened women. Essential components of a successful program are a high coverage rate of the female population, screening at regular intervals, well-trained clinical and laboratory staff, and an efficient follow-up and treatment system. Deficiencies in any of these areas may lead to a failing screening system. Thus, the most important reason for the remaining mortality from cervical carcinoma in developed countries is lack of complete coverage. It is questionable if new and more expensive technologies will be able to renmedy the remaining failures of the system if no improvement in the coverage rate is achieved. Screening errors do occur but represent only a small fraction of screening failures. Currently, there are a number of terminology systems around the world; thus, a unified terminology is currently not a realistic goal.