BACKGROUND Intestinal parasitic infestations are associated with acute and chronic diarrhoea in HIV patients. Almost all the HIV/AIDS patients are susceptible to parasitic infections; the risk is more among those individuals whose immunity is very low. The aim of this study was to determine the prevalence of Isospora belli in HIV patients with diarrhoea. MATERIALS AND METHODS A total of 250 HIV patients were included. Stool examinations as fresh wet mounts and modified acid-fast stain and CD4 cells counts were also performed. RESULTS GIT pathogens were found in stool of 74 (29.6%) patients with diarrhoea. The prevalence of Isospora belli was 2.7% among HIV/AIDS patients with diarrhoea. The common coccidian parasite found was Cryptosporidium parvum with a prevalence of 63.5% and non-coccidian parasite was Entamoeba histolytica with a prevalence of 28.3%. The CD4 count in patients with diarrhoea of 39 patients (52.7%) was less than 200 cells/uL, 31 patients (41.8%) between 200 - 500 cells/uL and 4 patients (0.05%) greater than 500 cells/ uL. CONCLUSION Even though the incidence of Isospora belli in HIV infected diarrhoea patients is very less when compared to the other GIT pathogens, routine stool examinations to be done for Isospora belli also so that it can reduce the morbidity and mortality associated with the GIT pathogens.