From May to December 2009, the Clinical Microbiology department of Da Nang hospital and the NK-Biotek have applied the sequencing technology to identify the genotypes, the mutations responsible for Lamivudine and Adefovir resistance and the precore, core promoter mutants on the HBV detected in 149 chronic hepatitis patients in Da Nang with HBVDNA [+]. These studied patients have been included 97 men (65 percent), 52 women (35 percent), average age: 30.9 + ? - 10.4 , 113 with HBeAg [+] (85.8 percent) and 36 with HBeAg [-] (14.2 percent) . Results: 126 patients with genotype B (84.4 percent) and 23 (15.7 percent) with genotype C were detected. 19patients (12.9 percent) of genotype Band C have carried the mutations for Lamivudine resistance, included: M2041 (21.1 percent), L180M/M204V (42.1 percent), M2041/ L801 or V207M (21 percent). 36 patients were detected HBeAg (-) and among these patients, 19 (14.1 percent) have been detected the mutation for precore (13 patients with 8.7 percent) and core promoter (6 patienst with 4 percent).