Recent discoveries have provided the compelling evidence that stem cell populations within each individual tumor are key contributors of therapy failure regardless of whether these populations are transient or stable. Thus, it is becoming increasingly clear that efficient tumor treatment requires eradication of the entire CSC population. The potential role of CSCs in tumor initiation and relapse has motivated an investigation of the CSCspecific treatments. However, development of the therapeutic strategies targeting CSCs might be challenged by a high diversity and plasticity of CSC features. Moreover, taking in account that an origin of CSC remains controversial and accumulating experimental evidence suggests a possibility of tumor cell reprogramming, efficient anti-cancer treatment should eradicate both CSCs and tumor bulk as well as prevent tumor dedifferentiation. In this article we discuss new insights into the stem cell concept of tumor development, review the treatment strategies eradicating CSCs that have been evaluated in preclinical and clinical studies and summarize the strategies to identify new CSC-targeted therapy.