A health education campaign designed to encourage women between the ages of 18 and 70, especially 'older' women (defined as those 50 and over), to have a Pap smear took place in New South Wales (NSW), Australia in early 1988. The campaign involved the mass media, some related community activities and mailing of an educational package to all General Practitioners. According to a sample survey the media campaign was recalled by just over 40% of its target audience. Outcome evaluation was based on the analysis of Pap smear records for a representative 10% sample (N = 338 000) of women registered with the Australian universal health insurance scheme in NSW and three control States. From logistic regression models we estimate that, for women over 50 years and older in NSW, there was a 30% increase overall in Pap smears during the 4 months following the campaign and a 50% increase amongst those who had not had a smear in the previous 2 years. Smaller increases were observed in some other States. Increases of 13-20% were observed among the younger age groups in NSW. Although the campaign appears to have prompted short-term increases in screening rates, the effect is too small to make a substantial impact on the size of the under-screened population.