Despite the progress that has been made in oncology in recent years, the increasing number of cases of cancer forces the search for new, more effective, and above all, safer therapeutic strategies. Immunotherapy, which is based on the mobilization and strengthening of the body‘s own defence mechanisms, perfectly fits this trend. This is important because cancer cells often ‘sneak out’ of immune surveillance and thus gain the possibility of uncontrolled growth and spread throughout the body. Strengthening and improving the immune response towards recognition/detection, and at the same time, destroying cancer cells is largely based on the modification of immunocompetent cells directly involved in the anti-cancer response. Because of the fact that lymphocytes NK (natural killer cells) are the first line of the body‘s defence against cancertransformed cells, hope is placed in them for a breakthrough in cancer treatment. Research on NK cells biology has allowed a better understanding of their huge therapeutic potential, and the achievements of modern medicine have enabled their effective use in cancer immunotherapy. This paper presents the current state of knowledge about the possibilities of using NK cells in cancer immunotherapy, in particular, adopted therapy using NK cells, antibody-dependent cellular cytotoxicity, strategies based on NK cell stimulation with cytokines, or blocking their inhibitory receptors.