Objective: During the 2000 to 2001 influenza season, distribution of influenza vaccine was delayed, and national self-reported vaccination rates declined. The purposes of this study were to characterize missed opportunities for adult vaccinations and assess the impact of the vaccine delay on missed opportunities for influenza vaccination as recorded in medical records.Methods: In a cross-sectional analysis, medical record data from 217 adult patients aged >65 years in primary care practices that received influenza vaccine supplies late in 2000 were used to assess rates and missed opportunities to vaccinate. Missed opportunities were defined as visits in which there was no record that vaccine had been given, discussed, or refused by the patient.Results