The aim of this article was to identify factors influencing the purchasing decisions of individual buyers represented by Polish doctors on the dairy product market, taking into account the demographic variable of the respondents’ age. This article is based on a survey conducted among 201 Polish doctors using the CAPI (Computer-Assisted Personal Interview) method. The collected primary data was subjected to quantitative analysis, including both a description of general trends and the identification of differences in responses between distinct age categories of respondents, as well as the identification of hidden factor structures. Conducting a study with a group of doctors perceived as experts fills a research gap in the literature and makes an important contribution to the discussion on the factors shaping the purchasing behaviour of doctors as buyers. The research revealed differences in the assessment of the importance of motivators influencing purchasing decisions for dairy products between groups of doctors separated by age. Younger respondents (aged 27–44) attach greater importance to the influence of marketing activities at the point of sale and the health attributes of dairy products, while older respondents (aged 45 and over) attach greater importance to aspects related to trust and safety as well as consumer trends. Hidden (latent) factors influencing purchasing decisions in the surveyed age-based groups of doctors were also identified in comparison with the total number of respondents, and consumer segments were identified based on the similarity of factor profiles. The results of this study can be used both by companies in the dairy sector in the process of designing marketing strategies for dairy products and by institutions influencing public health.