A bacteriological study of drinking water in three peripheral neighborhood of Asunción was performed. the sample were taken at nine homes dwellers were asked a questionnaire. The sample were taken in sterile 1-liter bottles from: 1. Water kept in 50 lt-plastic buckests; 2. Directly from the tap. At the time of sample taking, several children have acute diarrhea, some of them with several days of duration. The sample were filtered through 0.45 mu Millipore membranes and the material retained on the filter was cultured on S.S agar medium and incubated at 37 ºc overnigth. On the other hand, 10 ml of the sample were cultured in alkaline peptone, pH 8.5, peptone broth and selenite borth and incubated at 37 ºc for 12 h. Subculture was performed in TCBS agar, EMB agar and Ss agar respectively. Biochemical characterization of the growing micoorganisms isolate were Salmonella ssp, Enterobacter ssp and Prosteus ssp. Six samples were negative for microorganisms