In a country with a high prevalence (16%) of chronic serum HBsAg carriers like Romania there is a special interest in the diagnosis, epidemiology, clinics, pathology and treatment of HBV infection The idea of HBV genotyping arose from the need of understanding the complex interactions between virus and host. The purpose of this article is to present a study which aimed to identify the circulating HBV genotypes in Romania. correlate them with the clinical outcome and by HBV genotyping, to make a selection of patients for the most appropriate antiviral therapy. 130 patients were selected from different areas of the spectrum of HBV infection in which a quantitative determination of HBV-DNA was performed. HBV A genotype is associated with the inactive carrier status: a symptomatic HBV-HDV was identified in the double infection. The HBV D genotype has the most common HBV genotype (66%) and is associated with active viral infection and hepatocellular carcinoma. Long term HBV chronic infection revealed a mixture of A and D genotypes in most cases. For a proper selection of patient for the antiviral therapy, we should mandatorily genotype the HBV virus before the onset of treatment and all genotyping data must be correlated with liver biopsy assessments.