Antiretroviral Therapy is classified in six classes and acquired great achievements in HIV inhibition, but this advantage can be affected by developing drug resistance. The combinations of antiretroviral (ARV) drugs have been proven as effectiveness key to control the progression of AIDS; however, these benefits may be compromised by drug resistancy. Thus, drug-resistance testing has become an important tool to the management of HIV-infected patients. Viral RNA was extracted from the plasma by using the QIAamp→ Viral RNA kit (Qiagen, Germany) according to the manufacturer's protocol. RT-PCR performed with the one-step PCR kit (Qiagen, Germany) and Nested PCR.