Over the last decades, tremendous efforts have been made to strengthen childhood immunisation programs. However, the burden of influenza and pneumococcal infections remains disturbingly high in adults and elderly. We conducted a cross-sectional self-administered mail survey to identify characteristics associated with low use of recommended vaccines in adult patients attending routine primary care appointments in Switzerland. Tetanus vaccination was reported by 84% of respondents aged 16-34, and by only 42% of respondents aged 65 or more. For influenza and pneumococcal vaccination, of high-risk patients (age > or =65 or history of diabetes, kidney, heart, or chronic pulmonary disease), only 41% were on schedule for influenza and 6% for pneumococcal vaccination. Compared with patients from the German- and Italian-speaking areas of the country, patients from the French-speaking region were more likely to report past immunisation against influenza and pneumococcal disease or a recent physician's recommendation for immunisation against influenza, but equally likely to have ever refused influenza vaccination. For all three diseases, area of residence, physician's recommendation for immunisation, and patient's perceived usefulness of vaccination were independently and significantly associated with vaccination status. Although patient's opinion is an important determinant of vaccination coverage in adults, lack of physician's encouragement accounted for most missed vaccination opportunities in this study. The higher vaccination coverage among patients from the French-speaking area suggests that the promotion campaigns carried out in this region effectively improved influenza vaccine use. Interventions designed to increase vaccination coverage in adults must help providers incorporate immunisation in routine health care.