The multicellular behavior of bacteria has been the subject of much recent interest. This behavior includes coordinated control of virulence, luminescence, competence and biofilm formation; each of these appears to be regulated or influenced by quorum sensing. An understanding of what biofilms constitute, and how they develop, is emerging. It is clear that biofilm formation is a carefully orchestrated process that is dependent on quorum sensing. Somewhat surprisingly, several independent observations have noted an important role for DNA in the structure of biofilms. Recent studies describe a mechanism for linking DNA release to quorum sensing, providing a possible mechanism for the coordinated release of DNA, and its integration into a biofilm. A review of the literature reveals that similar observations have been made for biofilms of both Gram-positive and Gram-negative organisms. Further study will determine whether this is a general trend, however.