Introduction: Recent studies have indicated the COVID-19 pandemic has disrupted routine vaccinations. This study describes the prevalence and characteristics of children and adolescents experiencing disrupted routine vaccination and other medical visits in the U.S. between January and June 2021. Methods: The National Immunization Surveys were the source of data for this cross-sectional analysis (n=86,893). Parents/guardians of children aged between 6 months and 17 years were identified through random-digit dialing of cellular phone numbers and interviewed. Disrupted visits were assessed by asking: In the last 2 months, was a medical checkup, well-child visit, or vaccination appointment for the child delayed, missed, or not scheduled for any reason? Respondents answering yes were asked: Was it because of COVID-19? Sociodemographic characteristics of children/adolescents with (1) COVID-19–related missed visits and (2) non-COVID-19–related missed visits were examined. Statistical differences within demographic subgroups were determined using t-tests, with p-values