Research on new antivirals drugs applied in the treatment of chronically HCV infected indicate that even the most perfect therapeutic molecules do not guarantee 100% efficacy. Since the beginning of the history of HCV infection treatment clinicians looked for predictors of treatment efficacy. Numerous studies confirm the high probability of cure in patients who cleared HCVinfectional 4 and 12 weeks of therapy. However despite of viral factors, recent research demonstrated predictive role of some host dependent factors. The most important role seems to play genetic factors including polymorphism rs12979860, as well as chemokins including first of all CXCL10 (IP-10). Very interesting seems to be also results of studies on association between vitamine D concentration and treatment efficacy. However in the future the most important predictive factor remain probably early on-treatment viral response.