In Poland, primary care physicians are the most used and most trusted source of information on immunisation. We aimed to explore factors influencing support for vaccinations among physicians employed in the childhood immunisation programme, in order to inform education of healthcare workers and programme organization. In June-July 2017, we carried out a national cross-sectional survey of physicians working in randomly selected primary healthcare practices, and interviewed them by telephone. We assessed support for vaccinations using an ordinal scale (0-6) comprised of three equally weighted questions on the respondent support of the programme and vaccination of self and family. We also created a scale (0-3) based on correct answers to vaccination myths. We used ordered logistic regression to investigate factors independently influencing support for vaccinations, reporting the proportional odds ratios and 95% confidence intervals for one unit increase in the support score. Of 2,609 respondents contacted, we interviewed 500 (19%). The median vaccination support score (0-6) was 5 (IQR 2). After adjusting for other variables, we did not find significant effects of sex, medical specialty, adhering to recommendations, attending a conference in previous year, using non-scientific sources of information and self-assessed knowledge on vaccination support score. Age over 60 years, correctly addressing vaccination myths and use of one or more than one scientific sources of knowledge, significantly improved support for vaccinations (aOR = 1.97, 1.57, 3.09 and 2.68, respectively). We recommend to increase the amount, quality and accessibility of evidence-based educational materials for primary care physicians working with childhood immunisations.