In Gram-positive bacteria, cell-to-cell communication, also called quorum sensing (QS) mainly is dependent on extracellular signaling oligopeptide pheromones, which stimulate a response either indirectly, by activating a two-component phosphorelay, or directly, by binding to cytoplasmic effectors. The oligopeptide pheromones production and secretion are initiated in response to specific environmental stimuli or stresses. These pheromones are biosynthesized through different pathways and some have unusual functional chemistry as a result of posttranslational modifications. In the cells of Bacillus subtilis and Streptococcus pneumoniae this system controls the acquisition of the state of competence, while in Staphylococcus aureus it regulates virulence. The review aims at giving an updated overview of these peptide-dependant communication pathways.