Healthcare associated infection, which can occur in medical institutions, can affect patients, medical practitioners and visitors. In developed countries 5-10% of patients who are accepted for hospital treatment due to acute disease, get the infection that wasn’t present during the patient reception process, not even in the incubation stage. Recognition of risky factors, monitoring and taking emergency actions in order to put the infection spores can survive for more than six months. The most important risk factors for under control, will reduce the number of diseased people, mortality and primary disease expenses. Part of healthcare associated infections manifest through diarrhea and gastroenteritis, which are caused by viruses and certain bacteria. According to literature, over 50% of reports about epidemics in hospitals are about Norovirus. When it comes to a problem of pathogen transfer, major part of it is visible in pediatric departments, whereas diarrhea is caused by Rotavirus, Adenovirus and Astovirus. Clostridium difficile is anaerobic bacteria which can cause diarrhea and whole range of infection symptoms. It is familiar that this is transferred in hospital environment, because it is spore-forming bacteria. We should be aware of the fact that in certain environment disease acquirement are antimicrobial therapy, longer hospitalization period, chronic diseases, antiulcer therapy and similar situations. Concerning other causative agents of diarrhea acquired during hospitalization period, we should mention certain bacteria like Campylobacter spp., Escherichia coli, Shigella spp., Salmonella spp., Yersinia enterocolitica, Aeromonas, Plesiomonas, Edwardsiella; bacteria tocsins of Clostridium perfringens, Clostridium botulinum, Klebsiella oxytoca, Bacillus cereus, Staphylococcus aureus, Bacteroides fragilis; enterovirus, calcivirus, coronavirus, reovirus viruses. Causes of diarrhea acquired during a hospitalization period, are typically transmitted in a fecal-oral route. It can be caused by food, water, medicaments, tools, instruments and equipment, but not as often as in the previous case. Hand hygiene is the most important process of infection control, conveyed by healthcare employees in order to reduce infection transmission. Environmental hygiene, which means intensive cleaning of all potentially contaminated surfaces, reduces the environmental pollution by causative agents. Personal protective equipment also reduces infection transmission. Appliance of contact isolation method is also an effective way of preventing and suspending infection spreading from patient to patient, as well as from a patient to healthcare employees.