The temperature dependences of magnetic properties and magnetic field behavior of Co/Gd/Co thin-film three-layer systems obtained via ion-plasma magnetron sputtering are studied. The thickness of cobalt layers is 5.0 nm and of Gd layers ( t Gd ) varies from 3.0 to 10.0 nm. The bulk magnetic characteristics of the samples were measured on a vibration magnetometer with an external magnetic field oriented parallel to the plane of the samples. The influence of the temperature and the thickness of a Gd layer on the shape of the hysteresis loops, the values of the magnetic moment m and the coercive force H C are discovered. In particular, when the temperature changes from 100 to 300 K, the coercive force decreases, and the magnetic moment increases at a temperature above 150 K. The m value decreases with an increase in thickness of gadolinium.