The spectacular progress which was present in the past few years in the field of genome sequencing, together with the appearance on the market of some high performance devices in this field, the reduction of the costs regarding the analysis of the samples and the standardization of some protocols, has led to the establishment and introduction of the new generation of sequencing techniques in clinical diagnostic labs. An important role is played by the implementation of this technique in the oncology clinics. In this context, we found it appropriate to discuss in this chapter about the role of next-gen sequencing in determining the genetic probabilities of occurrence of oncological pathologies in the healthy population, the screening of these diseases at the population level, the diagnosis and classification of this pathology, the establishment of the therapeutic conduct using the technique, as well as the progression of the disease. In this chapter, we intend to discuss in particular the involvement of this technology in hemato-oncological diseases.