OBJECTIVE: To assess whether chronic disease is a barrier to screening for breast and cervical cancer. DESIGN: Structured medical record review of a retrospectively defined cohort. SETTING: Two primary care clinics of one academic medical center. PATIENTS: All eligible women at least 43 years of age seen during a 6-month period in each of the two study clinics (n = 1,764). MEASUREMENTS AND MAIN RESULTS: Study outcomes were whether women had been screened: for mammogram, every 2 years for ages 50-74; for clinical breast examinations (CBEs), every year for all ages; and for Pap smears, every 3 years for ages under 65. An index of comorbidity, adapted from Charlson (0 for no disease, maximum index of 8 among our patients), and specific chronic diseases were the main independent variables. Demographics, clinic use, insurance, and clinical data were covariates. In the appropriate age groups for each test, 58% of women had a mammogram, 43% had a CBE, and 66% had a Pap smear. As comorbidity increased, screening rates decreased (p < .05 for linear trend). After adjustment, each unit increase in the comorbidity index corresponded to a 17% decrease in the likelihood of mammography (p = .005), 13% decrease in CBE (p = .006), and 20% decrease in Pap smears (p = .002). The rate of mammography in women with stable angina was only two fifths of that in women without. CONCLUSIONS: Among women who sought outpatient care, screening rates decreased as comorbidity increased. Whether clinicians and patients are making appropriate decisions about screening is not known.