Magnetocaloric effect (MCE) is a heating or cooling of a magnetic material when the applied magnetic field changes. At the heart of the MCEs lays coupling between the magnetic moments and external magnetic field, and in some cases the MCE involves structural transitions concomitant with magnetic transitions. MCE can be used for cooling and may offer larger efficiencies than a conventional vapor-cycle refrigeration. The current goal is to find cheap and efficient magnetocaloric materials that can operate around room temperature. Structure and properties of known magnetocaloric materials are discussed and compared.