These are six different classes of antiretroviral drugs that are nucleoside/nucleotide reverse transcriptase inhibitors(NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), fusion inhibitors, CCR5 inhibitors and integrase inhibitors. NRTIs are thought as backbone of HAART(highly active antiretroviral therapy) and tenofovir/emtricitabine is one of the most important combinations in NRTIs. Efavirenz has been one of the most effective key drugs of HAART but rilpivirine and etravirine have been options recently. PIs have been also effective key drugs. Lopinavir/ritonavir (LPV/RTV) had been a last option to virological failures but adverse events such as diarrhea, nausea and hypertriglycemia of these drugs were severe. Darunavir/ritonavir is more virologically effective PIs with milder adverse events than LPV/RTV.