CD4 enumeration in the peripheral blood is an essential tool for the laboratory monitoring of HIV- infected patients. The objectives were to study the CD4+T-cell counts in patients on HAART,to study the relationship between the TLC and CD4 counts and to study the CD4 changes in different ART regimens.100 HIV positive patients were started on ART from August 20th 2006 to 19th August 2007 at ART centre, K.R. Hospital, MMC&RI, Mysore. Baseline CD4 counts, CBC and biochemical investigations were conducted before ART initiation.Theyweresubsequently followed up every 3 months till the end of the study period. A control group of 50 was included and CD4 counts were determined. Data analysis was done using SPSS software for windows evaluation version 14. The mean baseline CD4 counts were 110 cells/cu.mm. There was a median increase of 184.5 cells/cu.mm after 6 months of follow-up. A highly significant correlation was observed between TLC and CD4 counts both before and 6 months after ART. All the ART regimens showed a significant increase in CD4 counts after 6 months of HAART, irrespective of the regimen used. Thus, ART was beneficial in a majority of the patients.