BACKGROUNDThe widespread use of HAART therapy resulted in marked decline in the incidence of most AIDS defining conditions and mortality, both in the developed and developing world. As the scope of ART in developing countries continues, the number of patients failing in first line therapy and switching to second line therapy will inevitably increase. The aim of the study is to assess the therapeutic response by CD4 count and plasma viral load in HIV patients who received 2 nd line regimen consisting of tenofovir, lamivudine, Ritonavir and atazanavir.