Background. It is estimated that approximately 50% of women in Australia with intellectual disability will live to 70 years of age and as a result many will fall within the age group at highest risk for breast cancer (50-69 years).Methods. Subjects were identified through the Western Australia Disability Services database. To determine the number of women diagnosed with breast cancer during the period 1982-2000, individual records (n = 2,370) were linked to the Western Australia Cancer Registry and the Mammography Screening Registry.Results. The incidence of breast cancer among women with intellectual disability was 64.0 per 100,000 person-years, by comparison with 146.7 per 100.000 person-years in the general population. The uptake of breast cancer screening was examined in a subgroup of 380 women, 34.7% of whom had used mammographic screening, as opposed to 54.6% screening uptake in the general population. Failure to use screening services was highest in women who were unmarried, and was positively associated with severity of intellectual disability, presence of physical disabilities. and urban residence.Conclusions. The lower incidence of breast cancer in women with intellectual disability may in part be attributable to decreased life expectancy. but it also appears to reflect significant under utilization of the readily available screening services. (C) 2003 American Health Foundation and Elsevier Inc. All rights reserved.