Newly identified metabotropic GPR17 receptors are structurally related to purinergic P2Y receptors and cysteinyl leukotriene receptors. Re- cent studies showed that they play an important role in maturation of oligodendrocyte precursor cells. This review describes structure and pharmacological characterization of GPR17 receptors. It also summarizes knowledge about role of GPR17 receptors in physiology and patho- logy of nervous system, with special attention to remyelination processes.