Background: Tenofovir has been recently introduced in our country as first line therapy in HIV infection but limited data available on safety profile __ampersandsignamp; tolerability in Indian population of patients. This study focused on change of haemoglobin level due toTenofovir given as a first line anti retroviral therapy in HIV infected patient. Aims of the Study: To show the change of haemoglobin level due to tenofovir in tenofovir based first line anti retroviral therapy in HIV infected patient. Materials __ampersandsignamp; Methods: We studied descriptive __ampersandsignamp; longitudinal study in Art center in Murshidabad medical College __ampersandsignamp; hospital, west Bengal, July 2014 to June 2015.Our study included 107 HIV infected patient (aged 18 years and above) attending Art center, Murshidabad medical College __ampersandsignamp; Hospital who will be started on Tenofovir based 1st line Art (according to NACO guideline) except Pregnant women, patients with serum creatinine __ampersandsigngt;1.2mg/dl __ampersandsignamp; unwilling for consent. Discussion: During this period 10 of them left the study due to lack of follow up. The study population had overall weight gained __ampersandsignamp; increased by haemoglobin at the end of the study. Results: This study shows that tenofovir is well tolerable drug. Tenofovir therapy is associated with mean weight gain and increase in haemoglobin level. Conclusion: Tenofovir therapy is associated with mean weight gain and increase in haemoglobin level.