The development, survival and activation of lymphocytes is controlled by a multitude of extracellular signals in the form of soluble or membrane-bound ligands. Binding of these ligands to receptors on the lymphocyte surface is translated into intracellular signals that are processed in various ways inside the cell and determine its fate. The processing of an incoming signal involves amplification, diversification and termination. Feedback signalling loops have an essential role in the control of these processes, yet our knowledge about these regulatory loops is limited. However, several new feedback regulatory circuits have been recently discovered in lymphocytes and it is probable that more of these circuits will be found in the near future. Here, we give an overview of the present knowledge and working principles of such feedback loops.