As in other developing countries, diarrhoea is a major cause of morbidity and mortality in Indonesia. It is estimated that at least 4-5 million deaths per year in the world are caused by acute diarrhoea. In Indonesia, 40% of deaths in the first 2 years of life is caused by acute diarrhoea. This study is to assess the microbial agents of diarrhoea! disease, from patients of 2 hospitals in Jakarta. Rectal swabs for bacteriological examination were collected from patients at the admission using Cary & Blair as a transport media. Stools for Rota virus examination were collected in a tube container and kept at 4- 6°C before further processing. Conventional bacteriological procedures were performed for isolation and identification of bacterial agents. Enterotoxigenic E. Coli (E T E Cj was examined by ELISA for LT and by intragastric inoculation of suckling mice for ST. Campylobacter was incubated at 42°C in a candle jar using desiccator as a jar. The isolation results from 1937 specimens collected were V. cholera 01 50,2%, Rota virus 31,0%, ETEC 6,8%, Campylobacter sp 4,8%, Salmonella sp 4,3%, V. parahaemolyticus 1,6%, NAG 0,9%, Shigella sp 0,8%, Y. enterocolytica 0,2% and mixed infection of 2 or 3 different agent 5%. Most of the V. cholera isolated were of the Ogawa sero-type (98,9%). ETEC consisted of 69,2% LT alone, 21,4% ST alone and 8,9% both LT and ST. The most prevalent among 10 Salmonella species isolated were S. oranienberg 34,9% and S. kreveld 21,7%. The most prevalent among 4 species of Shigella isolated were Sh. flexneri 43,8% and Sh. dysen-triae 31,3%. Diarrhoeal diseases were continuously found through the year with 2 peaks; one high peak in May, June and July and the other lower peak in December and January.