Considering that the current global problems are a trend towards increasing resistance of microorganisms to antibiotics and issues related to biofilm infections, the purpose of this review was to analyze modern data on the population level of biofilm resistance, which explains their increased resistance to antibiotics. One of the main introductory postulates is that the bacteria in a biofilm have not only genetic, but also phenotypic mechanisms of resistance to antibiotics, which is due to the population level of biofilm organization. This study revealed the main causes of phenotypic resistance of biofilms: quorum sensing, matrix composition, heterogeneity of microbial populations due to the biofilm architecture, and the mechanisms of persister cell formation. In conclusion, the relevance of considering the phenomenon of collective resistance of bacterial cells to antibacterial drugs in biofilm consortia in relation to infectious agents is summarized for a detailed understanding of the issue under consideration and the formation of appropriate programs in the clinical and preventive fields of medical science.