Introduction: The treatment outcomes under national antiretroviral therapy (ART) programme are being evaluated in ART centers in the country. We carried out this study to analyze the impact of first line antiretroviral therapy in HIV infected patients attending free ART. The main objective of this work is to determine the clinical and immunological failure rate at first-line treatment. Methods: We have conducted a prospective, observational cohort study of patients living with HIV who had suspected failure of first line ART using data collected under programmatic condition. Four hundred and three patients from ART center King koti, Hyderabad from January 1, 2017 to December 2018 was taken in the study. Results: Between January 2017 to December 2018, 403 patients were registered in the ART clinic. Of these, 318 (52.6%) were on ART. Females accounted for 48% and males constitute 51%. Patients had a mean age of 37 ± 12 yr, Median CD4 count was 560 cells/μl (IQR: 289-734). 13 patients (4.2%) were in clinical stage 3 and 10 (8.24%) in clinical stage 4 for HIV infection according to the WHO classification. CD4 T-cells counts were between 4 and 1591 cells/mm3 with 174 patients (56%) with CD4 count below 500 cells/mm3. Conclusion: The rate of immunological failure rate of first-line antiretroviral treatment of patients under treatment in King koti, Hyderabad is 7.5% for the year 2017and 18.