BACKGROUND Lack of information has been associated with patient anxiety or concern in a number of healthcare areas. OBJECTIVE (1) Identify the proportion of parents who agreed, were neutral, and disagreed that they had access to enough information to make a decision about immunizing their child; (2) examine how parents who agreed and disagreed differed with respect to sociodemographic characteristics, and their attitudes about immunizations, their child's healthcare provider, immunization requirements/exemptions, and immunization policymakers; and (3) identify if differences exist in specific immunization concerns. METHODS A sample of parents with at least one child aged < or =6 years (n=642) was analyzed using data from the HealthStyles survey conducted during July and August 2003. Odds ratios and the Mantel-Haenszel chi-square test were used for analysis. RESULTS Response rate for HealthStyles was 69% (4035/5845). The largest proportion of parents agreed they had access to enough information (67%) compared to parents who were neutral (20%) or who disagreed (13%). Compared to parents who agreed, parents who disagreed were more likely to be less confident in the safety of childhood vaccines (odds ratio [OR]=5.4, 95% confidence interval [CI]=3.3-8.9), and to disagree that their child's main healthcare provider is easy to talk to (OR=10.3, 95% CI=3.7-28.1). There was a significant linear trend in the percentage of parents expressing immunization concerns among those who agreed, were neutral, and who disagreed they had access to enough information (p<0.05; df=1). CONCLUSIONS While most parents agreed that they had access to enough immunization information, approximately a third did not. Perceived lack of information was associated with negative attitudes about immunizations and toward healthcare providers. Basic information about the benefits and risks of vaccines presented by a trusted provider could go a long way toward maintaining and/or improving confidence in the immunization process.