Children aged <2 years are at increased risk for influenza-related hospitalizations, and children aged 24-59 months are more likely than older children to visit a clinic, hospital, or emergency department with influenza-associated illness. In 2002, the Advisory Committee on Immunization Practices (ACIP) encouraged annual influenza vaccinations for children aged 6-23 months (and for household contacts of and out-of-home caregivers for children aged <2 years). For the 2004-05 influenza season, ACIP strengthened its encouragement to a full recommendation. For the upcoming 2006-07 influenza season, ACIP has further extended its recommendation to include all children aged 6-59 months (and their household contacts and out-of-home caregivers). Others recommended to receive influenza vaccination include children aged 6-18 years who have certain high-risk medical conditions, are on chronic aspirin therapy, or who are household contacts of persons at high risk for influenza complications. This report provides an assessment of influenza vaccination coverage among children aged 6-23 months during the 2004-05 influenza season. The findings demonstrate that vaccination coverage in that age group approximately doubled from the 2003-04 influenza season, with substantial variability among states and urban areas. However, the percentage of fully vaccinated children remained low, underscoring the need for increased measures to improve pediatric vaccination coverage and ongoing monitoring of coverage among young children and their close contacts.