K⁺ channels participate in many biological functions from ion homeostasis to generation and modulation of the electrical membrane potential. They are involved in a large variety of diseases. In the human genome, 15 genes code for K⁺ channels with two pore-domains (K_2P). These channels form dimers of pore-forming subunits that produce background conductances finely regulated by a range of natural and chemical effectors, including signaling lipids, temperature, pressure, pH, antidepressants and volatile anesthetics. Since the cloning of TWIK1, the prototypical member of this family, we have carried out a lot of work about their structure and biology. These studies are still in progress, but data gathered so far show that K_2P channels are central players in many processes including ion homeostasis, hormone secretion, cell development and excitability. A growing number of studies underline their implication in physio-pathological mechanisms such as vascular and pulmonary hypertension, cardiac arrhythmias, nociception, neuroprotection and depression.  During my presentation I will give a synthetic view of the most noticeable features of these channels.