We studied the microflora structure and resistance gathered from the biomaterial of patients and the environment objects of various departments at the National hospital of Pediatrics in Hanoi. 140 clinical samples of biomaterials from 74 patients treated in the intensive care unit, the infectious diseases and the gastroenterology departments were studied. A systematic approach including microbiological, epidemiological and statistical research methods was used in carrying out the study. Bacteria of the Enterobacteriaceae family (38.5 per cent) prevailed in the biomaterial of intensive care unit patients. Nonfermentative Gram-negative bacteria (46.5 per cent) occupied the leading positions in the infectious diseases department and Gram-positive bacteria (39.3 per cent) were in the gastroenterology department. Gram-positive flora (60.2 per cent in the intensive care unit and 50.7 per cent in the infectious diseases department) prevailed in the microflora structure gathered from hospital environment objects. We identified the prevalence of bacteria of the genus Enterobacteriaceae and non-fermentative Gram-negative bacteria with a wide spectrum of resistance in the departments of the National Hospital of Pediatrics.