We describe the level of agreement between patients and their physicians with respect to their use of the Pap smear, the symptoms present, and the smear results. The data derived from a case-control interview study of 181 newly diagnosed invasive squamous cell cervical cancer cases and 905 age-matched controls, a second case-control interview study of 250 cases of cervical dysplasia and 500 age-matched controls, and the medical records of attending physicians for all patients. Cases and controls in both studies reported more smears over the previous 5 years than their medical records indicated; also patients reported their last smear as more recent than noted in physician files. Cancer cases were somewhat more accurate on frequency and timing of smears than the other patient groups. Patients tend to report more symptoms at interview than recorded in their files. Disagreements on smear results were probably because of differences in terminology, especially in distinguishing invasive from pre-cancerous conditions; cancer cases tended to report some dysplasias as cancer, but the controls in both studies under-reported dysplasia. If high physician response rates can be obtained, we would prefer to use physician records as the basis of evaluation of screening programs, especially when accurate dating of screening events is required. However it is less clear whether physician records are to be preferred, if the evaluation is to take symptoms into account.