Protein kinase CK2 is a ubiquitous, essential, and highly pleiotropic protein kinase whose abnormally high constitutive activity is suspected to underlie its pathogenic potential in neoplasia and other diseases. A number of structurally unrelated CK2 inhibitors, tested on a variety of cells derived from tumours, including lymphomas, leukaemias, multiple myeloma and prostate carcinoma, display a pro-apoptotic effect which is roughly proportional to their in vitro inhibitory potency. In the present review we summarize the most recent discovery of potent and selective CK2 inhibitors and their prospective as future anticancer agents.