Hyperlactatemia is one of the important metabolic abnormalities in HIV infected patients. The prevalence of hyperlactatemia in natural course of HIV disease is approximately about 2%. Aim of this study is to estimate the prevalence of hyperlactatemia in HIV patients receiving two antiretroviral regimens, advocated by NACO by monitoring the plasma lactate levels. This study was taken up with 200 patients to compare the prevalence of hyperlactatemia of two commonly used NACO regimens (zidovudine+ lamivudine+ nevirapine) Vs (stavudine+ lamivudine+ nevirapine). The plasma lactate levels were estimated between 9 th to 18 th month after initiation of antiretroviral therapy. The comparision and correlation between plasma lactate levels, CD4 counts and haemoglobin percentage in both regimens was done. There was statistically significant rise in the plasma lactate levels (p<0.05) in both regimens. The increase in plasma lactate levels is more in stavudine group compared to zidovudine group. There was low degree of positive correlation between plasma lactate and haemoglobin in Stavudine group but negative correlation between Plasma lactate and CD4 counts in both groups. More focus is needed on Pharmacovigilance of NRTIs induced hyperlactatemia especially Stavudine.