Multicellular yeast kingdom. Recent findings on microbial populations opened new area of investigation where microganisms are no more considered simply as individual cells, but taken as constituents of highly organise communities (colonies, biofilms) occupying various surfaces. Despite limited, current knowledge in the field suggests existence of unique processes linked to microbial multicellular life style. We briefly describe some of the unique properties and behaviour of yeast cell populations living within multicellular colonies. These include signaling, cell differentiation and defence strategies.