Diarrheal diseases are major problem of developing countries. Though precise data on childhood mortality associated with diarrheal diseases in Nepal is not available, it has been estimated that approximately 25% of child death are asso-ciated with diarrheal disease, particularly acute diarrhea. The purpose of this study was to assess the incidence of bacte-rial pathogens causing acute diarrhea in children under 5 years of age. A total of 525 children with acute diarrhea in a children's hospital of Kathmandu, Nepal were enrolled between April 2011 and September 2011. The higher prevalence of diarrhea was in the age group of less than 2 years. Out of total 525 enrolled cases, protozoal parasites were found in 10.7% (56/525) of cases and helminthic parasites were found in 1.3% (7/525) of cases. Highest prevalence of 60.3% (38/63) of parasitic infection was found in the age group of 6 -24 months followed by 7.9% (5/63) in the age group of less than 6 months. Of the total enrolled cases E. histolytica were 6.7% (35/525) followed by Giardial lamblia 3.4% (18/525) and the least frequency was due to A. lumbricoides constituting 0.6% (3/525). The aim of this study was to know the parasitic agents causing acute diarrhea in children.