BackgroundIn Japan, a number of people who die from influenza are still increasing however seasonal influenza immunization rates among children are still low and estimated to be around 30%. Given these circumstance we organized questionnaire surveys from 2009 to 2010 to examine the factors influencing awareness of mothers under frame work of Health Belief Model (HBM) that affect seasonal flu immunization acceptance among children. MethodFrom 2009 to 2010, we sent questionnaires to randomly selected university graduated women. The questionnaire asked their age, seasonal flu immunization status of their children, working status, subjective life standards, regions where they live, perceived severity of flu to their children, perceived susceptibility to flu of their children, perceived efficacy or non-efficacy of flu vaccination on their children, barriers to vaccination such that flu vaccination is non-mandatory, fear for side effect, busy and others, cues to the action such as family doctors recommendations and willing to pay (WTP). After the correlation of each variable was tested by spearman test (SPSS 17.0) adjusted logistic regression analysis predicting routine vaccination was done. Results; we sent 554 questionnaires to women and 226 mothers (Age 44.67±5.09) responded and 220 responses were analyzed. Among children of respondents, 41.2% were routinely flu shot vaccinated. From the multivariate logistic regression model, HBM framework showed that perceived susceptibility to flu of their children's (aOR=1.46, p>0.05), perceived severity of flu (aOR=1.14, p>0.05) to their children, perceived non-efficacy of flu vaccination on their children (aOR=0.12, p<0.01), and cue to the action such as family doctors’ recommendations (aOR=2.47, p<0.01) and knowing of the flu vaccination subsidy (aOR=1.96, p>0.05) were positive factors for flu immunization acceptance. On contrary, barriers such as subjective lower life standard (aOR=0.59, p<0.05), flu-shot was not mandatory (aOR=0.15, p<0.01), fear from side effects (aOR=0.31, p<0.05) and number of children (aOR=0.64, p<0.05) were negative factors. Discussion; Correct education and knowledge dissemination for mothers are necessary to raise the low coverage rate of their children in order to prepare potential future flu pandemic.