National surveys of adult vaccination indicate moderate self-reported immunization rates in the US, with limited validity data. We compared self-report with medical record abstraction for 820 persons aged > or =66 years from inner-city health centers, Veterans Affairs (VA) outpatient clinics, rural and suburban practices. For influenza vaccine, sensitivity was 98% (95% CI: 96-99%); specificity was 38% (95% CI: 33-43%). For pneumococcal polysaccharide vaccine, sensitivity was 85% (95% CI: 82-89%) and specificity was 46% (95% CI: 42-50%). The VA had the highest sensitivity and lowest specificity for both vaccines while the converse was true in inner-city centers. High negative predictive values indicate that clinicians can confidently vaccinate based on negative patient self-report.