PURPOSE: To determine if infant vaccinations are associated with childhood asthma among full-term infants. The secondary objective was to describe relationships between characteristics of infant wheezing and childhood asthma. METHODS: We used baseline data from a study of infant wheezing that selected full-term infants born into a health maintenance organization (HMO) during 1991-1994, continuously enrolled for at least 12 months and without perinatal pulmonary or other selected conditions. Information had been abstracted for infancy (0-18 months) regarding wheezing, vaccinations and asthma risk factors. Using automated data, we identified asthma cases in 1998 among those enrolled for at least 6 months during the year. RESULTS: A total of 1778 full-term infants met our study criterion and 9% had asthma in 1998. Childhood asthma was not significantly associated with having received Hepatitis B vaccine or age at first Hepatitis B vaccine; number of whole-cell pertussis, Haemophilis influenzae type b or oral polio vaccine doses; having received measles, mumps, rubella vaccine; or total number of vaccine doses combined. Childhood asthma was significantly associated with number of infant wheezing episodes. CONCLUSIONS: Our findings do not support concerns that vaccines are associated with increased risk of asthma but confirm that frequency of infant wheezing is associated with childhood asthma.