Diluted magnetic semiconductors (DMS) are interesting because of the interplay between the electronic and magnetic subsystems. Selected magnetic properties of IV–VI DMS are described, looking at the similarities and differences between magnetic properties of II–VI, IV–VI, and III–V DMS. The influence of the crystalline and electronic structure of the material on its magnetic properties is focused on, especially on the exchange interactions among magnetic ions. Methods of determination of the exchange parameters are described by using different experimental techniques, such as measurements of magnetic susceptibility, magnetization, and specific heat. The development in the material technology from bulk crystals to thin films and nanostructures is followed.