© 2019 Croatian Conservation Institute. All rights reserved.In the gastrointestinal tract of honey bees (Apis mellifera), there is a unique collection of microorganisms, called microflora or microbiota, which have various mgeyietabolic activities in the bee crops, which can protect against various microbial threats, and is linked to powerful mechanisms of action in the bee immune system. The adult honey bees especially have a rich microflora. Their microbiome is considered to be one of the most important and remarkable factors in maintaining bee health. Like humans, honey bees (Apis mellifera) are social creatures and work cooperatively to ensure the continuity of life in the hive. In productive colonies, the increasing diversity of microbiota depends on various factors, from the developmental age of the bee to its feeding, from the geographical location of the hive to the local climate. The lack of diversity of the bacterial community may negatively affect the productivity of the bee hive. This review describes the diversity of the honey bee intestinal core microflora, which are of great importance for bee life, the ways in which they acquire the bacteria, how they colonize in the gastrointestinal tract of bee and their associated beneficial mechanisms for honey bee survival.